I have tried Project Reality mod, and i really liked the idea of the game. I played Battlefield 2: Project Reality mod, even it was not like Arma, but i still had nice memories, and I've met really great people there.
From what I've seen in Battlefield 2: Project Reality - I'm expecting really nice results from Arma and Project reality, but of course - first of all need to wait for full Arma 3 game, which hopefully will be released soon.
Have anybody checked what possibilities has Reality mod?