A good game, but has many problems and eventually just stops being fun. Fairly overrated.
Some of the problems I've noticed that frustrate me and many of my friends are that you get shot when they don't even have the cross-hair on you, the guns are inaccurate, a lot of guns aren't realistic to the time they were set, you die from being shot/stabbed in the foot, it takes too many bullets to kill and the bots are just retarded.
Until some of these problems are fixed, I'll stick to the more realistic and less frustrating FPS games like Battlefield, Halo and Killzone. Even though Halo and Killzone have things that would be considered unrealistic now, remember they are extremley far in the future with other galaxies involved.