Though most of them say AD700 is best for gaming, from my personal experience I prefer T500 more for gaming.
Mainly because, Ad700 is open ended and the seal is not proper, you can hear the sounds nearby, which can be a bit irritating while gaming IMO.
T500 are closed, perfect seal, infact the seal is as good as an IEM for me, it muffled the external sounds like an IEM, which I feel is ideal for gaming coz you only hear the in game sounds, no chance of any external sounds.
For me personally, it is easier to identify footsteps on T500 than on AD700.
But AD700 was on a different league when it comes to music, so it boils down to personal choice & usage pattern IMO.
P.S: I own both and this is my honest opinion about them, not biased towards anything
because I felt disappointed when someone suggested Ad700 for gaming and it turned out to be opposite when I bought