the thing about it is, it's pretty much the real war experience. the only difference is, you don't run and shoot yourself, instead you sit in the chair and keep clicking the mouse. but if you treat it right, it's a masterpiece.
of course, if you expect the Call of Duty experience from it, you're going to be sorely disappointed. and Bohemia did try to inject some of that CoD/BF feel into ArmA. that's the root of all the game's problems. c'mon. it's a sandbox game. the campaign suffers from the fact that you're very vulnerable at all times and your team is very small, facing hundreds of enemies (both infantry and light to heavy armor). of course they had to go heavy on scripted events to make the game fair towards the player.
I think this game is better suited for multiplayer. I've just watched a couple of videos of MP battles, it's unbelievable. Bohemia managed to combine RTS and tactical FPS, it actually works