You don't need to pass any of the online missions to get sniper training. You do, however, need to get at least 36/40 targets on the rifle training. The netcode seems fine to me, but then again, I am on DSL and live close to the Official servers. Up to 120ping seems pretty playable to me, unlike some other games where anything above 80 is terrible. Maybe its just because of the slow speed of the gameplay.
I get about 25-30FPS outdoors @1600x1200, 2xAA, and 2x AF. Indoors is anywhere from 50-70.
I think there is a problem with the server program; sometimes the server resets randomly (for everyone). Also, scoring for teams is bugged, sometimes it says my team has been eliminated when most of them are in fact still alive. Then there's the occasional client-side error that misses some of the apparel for teammates, ie. backpacks. This makes it frustrating when you see someone without a pack on, and after emptying a clip into them, they curse at you for a TK.
I do really like the ROE system, but its not perfect. 400 ROE (Rules of Engagement) and that person is autokicked. Motivates people to be a little more careful with their nades. Speaking of which, sometimes those nades have insane radii. I don't know how my own nade can kill me from 30 yards away
But overall, it's a very entertaining game and I think these issues will be resolved in the next patch.