Played Arma2 and PR for Arma2. Cool game, but still very clunky. BF3 is like butter, and Arma is like stop action animation. It looks great, but the gameplay is awkward.
Also, Arma in general is SUPER deep. It takes hours just to figure out how to shoot the gun, let alone all of the advanced features.
Arma is for folks that have 4-5 hours at a time to play video games.
I may end up getting Arma 3 just to check it out, but I still haven't really played Arma2.