Best military sim to date by far and a lot of fun to be had if you give it a chance.
The battles can be very intense as you have the ability to wage war with thousands of AI opponents and still remaining very realistic as one bullet can end your game for good, this is no COD or BF rambo run and gun bs this is a military sim and needs to be played as such in order to enjoy the game for what it is.
With that being said i could only recommend this game to those with high end pc's as arma 2 can be very demanding CPU and GPU wise, if you can exceed the recommended requirements then you should be able to run it fine yet it seems people with min specs tend to struggle.
Overall arma 2 sets out to do what it does best which is huge battles across wide open spaces with massive amounts of AI.