Big Bohemia Interactive fan. I played Operation Flashpoint and am still playing Arma 1 and Arma 2. Haven't got Arma 3 yet but I will soon.
Arma 2 CO V1.62 runs well on my system but from what I've seen of Arma 3 it runs like cr*p and I'll need a GTX 760 upgrade at least. Hopefully a few patches can make it run better.
Here's some tweaks to try to make Arma 3 run better. Apologies if this has already been posted but I don't have time to look through 117 pages.
The Arma games are certainly unique and huge and I enjoy creating missions with the editor. Anything you can think of you can just about do. The infantry combat and ballistics are among the most realistic I've seen in PC gaming.