Been almost 20 days since I got the Xperia S. Brilliant device and there really isn't much that I have to complain about 
So here's my "small" review. Pics will be uploaded by evening.
Design & Build Quality
The design is in one word - GORGEOUS !. The transparent bar at the bottom gives it a unique look and above it the design is almost monolithic, just like Sony monolithic design Bravia Tvs. Looks amazing and I can't help stare at my phone VERY often and appreciate the wonderful design. I absolutely love the design, though I wish it were a little thinner. But its really comfortable to hold though. The grip is very good and no slippery feel here, the phone's anti stain coating also helps and after 20 days its still as good as new with no stains or fingerprint marks on the body.
Unfortunately the three buttons above the transparent bar are not that responsive to a soft touch. But a firm touch does the trick.
Build Quality is also very solid, not much to complain about. The device feels really premium in the hands and everything seems well put together. The only slight problem I have with the Build Quality is the back cover. It could have been more solid.
Software and Performance
Xperia S is currently running Android 2.3.7 Gingerbread with Sony custom UXP. When I first saw the UI during the phone's launch at CES, I was blown away by how clean and elegant it looked. And it looks even better on the Xperia S screen
The Sony UI isn't too intrusive and is very pleasing to the eyes. Timescape and Facebook Inside Xperia are two big highlights but I can't tell you how good they work as I don't use either of them.
The Sony music player is fantastic though. The My music part looks similar to Windows Phone as has been mentioned everywhere.
Other apps Sony included are the power saver app, Xperia smart tags app, Live ware manager, Friends music & videos, DLNA app etc.
The clock and the weather widget are really nice but the Power Control/Toggle widget isn't quite nice. You need to click it twice to open the entire controls list and only then toggle on and off.
Performance is very smooth and largely free from any lag whatsoever. In the 20 days that I have had the phone, I think I experienced "lag" only 2 days and that too for about 3 seconds.
Never had the need to reboot either and the phone doesn't slow down over time.
Browsing is super smooth and I really don't feel any difference in smoothness while browsing on the XS compared to my laptop. No complaints here. Pages load fast and scrolling is smooth, no stutter or lags.
Benchmarks below
Multimedia, Screen & Camera
The Xperia S has a 4.3 inch 720p HD screen and it is nothing short of a beauty !!. It has highest PPI of any Android smartphone at 342PPI and is sharper than even the Iphone 4/4S retina display.
It is also extremely bright and at full brightness indoors can even blind you coupled with the super high sharpness
Watching videos on the screen is a treat and has very vibrant colors that truly POP. Except for blacks, I would say it has en edge even over an OLED display. Also colors are more natural on the screen than OLED screens.
Text is super crisp and reading websites without zooming in is possible. Even better than Iphone 4S for reading books !
Viewing angles are not amazing but then who looks at their phone screen from a 60/80/90/120 degree angle ?
At least I don't and head on, the Xperia S screen is more than a match for any other screen out there. Everything pops and makes you fall in love with the screen
It plays all video formats easily and even with the gallery app I could play almost all videos except for 1080p mkv which do play butter smooth but with no audio.
With third party apps like Dice player there is not a hint of stutter no matter what video you play.
Plays 1080p videos in the browser without breaking a sweat too.
Also transferring large files is a breeze as the transfer speed is brilliant. I transferred a 600mb movie to the phone in 55 seconds !
Audio Quality is very good too. For a phone it's very commendable but compared to a quality dedicated PMP like my Sony Walkman A series, its quite less loud at full volume. Though for most people it shouldn't be an issue but then I haven't heard any other smartphone that has the same loudness as my Walkman.
Overall audio quality though is very good and for some reason I seem to enjoy listening to music on the Xperia S a lot now and its been a week since I even switched on my walkman. Oh and the stock earphones sound quite good !! Bassheads would like them for sure. Much better than the Htc Beats earphones
The bass is definitely not as deep as the Walkman but its quite good for a phone, the highs seems better though and almost on par with the Walkman. It has an equalizer so you can change the sound to whatever you like, along with Clear Bass which can be adjusted up to 10 points.
12 megapixel EXMOR R camera. Yup that's probably the biggest USP of this device and it doesn't disappoint. In daylight photos are sharp, clear and detailed with little noise. In low light conditions though you can get a horrible picture if you do not know how to get the settings right.
The Xperia S isn't the best camera phone in the world if you just want to point and shoot and not play around with the settings and have no patience.
But if you have some patience and are willing to play around with the settings then you will definitely come up with photos that would look better than almost any other smartphone out there except for the Nokia 808 pureview.
1080p videos are a smooth 30 fps and quality is great even in not so bright conditions.
The front camera also captures 720 HD video and the quality is really nice.
Sample pics below
Call Quality and Battery Life
Signal reception is excellent on the XS. I always get full bars whereas all other phones manage only 3 bars in my home. Call Quality is also brilliant on both sides the voices are clear and the noise cancellation works nicely as well.
The best call quality among all phones that I have owned and used in recent times.
Full 5 stars for signal reception and call quality
Battery Life was horrible for the first few days. It would discharge completely in about 6 hours with moderate usage. But it has settled now and I get between 18-30 hours of battery life depending on usage with about 3-4 hours of screen on time.
Overall
I love this phone to death. No major complaints just a few minor ones :
1. Still need to wait 2-3 weeks for ICS, but then that's fine as the update will be bug free and feature lot of cool new apps from the upcoming Xperia GX.
2. Wish the volume was a little higher via earphones. Also the speaker during phone calls is not that loud
3. Battery should have been of higher capacity
4. Screen could have done with deeper black levels
5. The three touch sensitive buttons at the bottom are not always responsive
So here's my "small" review. Pics will be uploaded by evening.
Design & Build Quality
The design is in one word - GORGEOUS !. The transparent bar at the bottom gives it a unique look and above it the design is almost monolithic, just like Sony monolithic design Bravia Tvs. Looks amazing and I can't help stare at my phone VERY often and appreciate the wonderful design. I absolutely love the design, though I wish it were a little thinner. But its really comfortable to hold though. The grip is very good and no slippery feel here, the phone's anti stain coating also helps and after 20 days its still as good as new with no stains or fingerprint marks on the body.
Unfortunately the three buttons above the transparent bar are not that responsive to a soft touch. But a firm touch does the trick.
Build Quality is also very solid, not much to complain about. The device feels really premium in the hands and everything seems well put together. The only slight problem I have with the Build Quality is the back cover. It could have been more solid.
Software and Performance
Xperia S is currently running Android 2.3.7 Gingerbread with Sony custom UXP. When I first saw the UI during the phone's launch at CES, I was blown away by how clean and elegant it looked. And it looks even better on the Xperia S screen
The Sony UI isn't too intrusive and is very pleasing to the eyes. Timescape and Facebook Inside Xperia are two big highlights but I can't tell you how good they work as I don't use either of them.
The Sony music player is fantastic though. The My music part looks similar to Windows Phone as has been mentioned everywhere.
Other apps Sony included are the power saver app, Xperia smart tags app, Live ware manager, Friends music & videos, DLNA app etc.
The clock and the weather widget are really nice but the Power Control/Toggle widget isn't quite nice. You need to click it twice to open the entire controls list and only then toggle on and off.
Performance is very smooth and largely free from any lag whatsoever. In the 20 days that I have had the phone, I think I experienced "lag" only 2 days and that too for about 3 seconds.
Never had the need to reboot either and the phone doesn't slow down over time.
Browsing is super smooth and I really don't feel any difference in smoothness while browsing on the XS compared to my laptop. No complaints here. Pages load fast and scrolling is smooth, no stutter or lags.
Benchmarks below
Multimedia, Screen & Camera
The Xperia S has a 4.3 inch 720p HD screen and it is nothing short of a beauty !!. It has highest PPI of any Android smartphone at 342PPI and is sharper than even the Iphone 4/4S retina display.
It is also extremely bright and at full brightness indoors can even blind you coupled with the super high sharpness
Watching videos on the screen is a treat and has very vibrant colors that truly POP. Except for blacks, I would say it has en edge even over an OLED display. Also colors are more natural on the screen than OLED screens.
Text is super crisp and reading websites without zooming in is possible. Even better than Iphone 4S for reading books !
Viewing angles are not amazing but then who looks at their phone screen from a 60/80/90/120 degree angle ?
At least I don't and head on, the Xperia S screen is more than a match for any other screen out there. Everything pops and makes you fall in love with the screen
It plays all video formats easily and even with the gallery app I could play almost all videos except for 1080p mkv which do play butter smooth but with no audio.
With third party apps like Dice player there is not a hint of stutter no matter what video you play.
Plays 1080p videos in the browser without breaking a sweat too.
Also transferring large files is a breeze as the transfer speed is brilliant. I transferred a 600mb movie to the phone in 55 seconds !
Audio Quality is very good too. For a phone it's very commendable but compared to a quality dedicated PMP like my Sony Walkman A series, its quite less loud at full volume. Though for most people it shouldn't be an issue but then I haven't heard any other smartphone that has the same loudness as my Walkman.
Overall audio quality though is very good and for some reason I seem to enjoy listening to music on the Xperia S a lot now and its been a week since I even switched on my walkman. Oh and the stock earphones sound quite good !! Bassheads would like them for sure. Much better than the Htc Beats earphones
The bass is definitely not as deep as the Walkman but its quite good for a phone, the highs seems better though and almost on par with the Walkman. It has an equalizer so you can change the sound to whatever you like, along with Clear Bass which can be adjusted up to 10 points.
12 megapixel EXMOR R camera. Yup that's probably the biggest USP of this device and it doesn't disappoint. In daylight photos are sharp, clear and detailed with little noise. In low light conditions though you can get a horrible picture if you do not know how to get the settings right.
The Xperia S isn't the best camera phone in the world if you just want to point and shoot and not play around with the settings and have no patience.
But if you have some patience and are willing to play around with the settings then you will definitely come up with photos that would look better than almost any other smartphone out there except for the Nokia 808 pureview.
1080p videos are a smooth 30 fps and quality is great even in not so bright conditions.
The front camera also captures 720 HD video and the quality is really nice.
Sample pics below
Call Quality and Battery Life
Signal reception is excellent on the XS. I always get full bars whereas all other phones manage only 3 bars in my home. Call Quality is also brilliant on both sides the voices are clear and the noise cancellation works nicely as well.
The best call quality among all phones that I have owned and used in recent times.
Full 5 stars for signal reception and call quality
Battery Life was horrible for the first few days. It would discharge completely in about 6 hours with moderate usage. But it has settled now and I get between 18-30 hours of battery life depending on usage with about 3-4 hours of screen on time.
Overall
I love this phone to death. No major complaints just a few minor ones :
1. Still need to wait 2-3 weeks for ICS, but then that's fine as the update will be bug free and feature lot of cool new apps from the upcoming Xperia GX.
2. Wish the volume was a little higher via earphones. Also the speaker during phone calls is not that loud
3. Battery should have been of higher capacity
4. Screen could have done with deeper black levels
5. The three touch sensitive buttons at the bottom are not always responsive
