There were some issues in the Beta initially but several patches corrected that. Full game should be fully functional.
I've heard a lot about ARMA but never tried it. Too many great games, too little time. I chose the Battlefield series to invest what time I have into. :)
Movement feels a bit clumsy compared to BF3, but the good old peaking around corners is back :) And the level of destruction is insane. You can almost blow up everything.