I've been using it to game with the PS3, here is the biggest problem you will have with your set-up. Audio. There is no output on the projector so you will have to use a digital audio cable from the ps3 to a sound system. I had to buy a converter to change it to RCA so that it would work with my system. Also it only has one input for HDMI. I just got a hdmi splitter box so its not an issue for me anymore.
Input lag would seem to be negligable, I haven't had any problems playing games, i've been playing lots of Uncharted 3 and Batman Arkham City, both in 3D and I'm having a great time, however the brightness is an issue.
Another point is the rainbow effect, this being a DLP, and not having the fastest colour wheel, I found it noticeable from the moment I first used the projector, so has my girlfriend and a few friends who have watched movies on it with me. I found that I eventually ajusted to it and don't notice it as much now, but it still bothers me occasionaly.
Overall it is a good projector, but I still would not recommend it. The picture quality is just workable. It's definetly not as sharp as my old projector. I bought it because I really wanted 3D for cheap and the 2d-3d sucked me in too. I got D538w-3D for under 700$.