Fun Free Online FPS
The problem I see most people complain about is how hard it is to buy items, because they cost too much... The game is designed to be that way, they don't want you to be able to get every gun and every item. You need to spend your money wisely, so you can get money faster, and eventually permanently own guns that you like to use. I think the weapon buying system is great, along with the tons of customization options.
I really wish I could think of something about this game that I don't like, but I can't think of much. It's definitely one of my new favorites, I suggest it to anyone considering.