A love it or hate it game
That said, there are a few features that are undiniably bad and good.
The Bad: Collision detection, you will often find charecters glitching into eachother, and dead people usually fall into the floor, but the problem doesn't affect the game much. The only big problem i found in the game was the AI. If you would watch your team fight for a while you'll realize that they can be bad shots at times. I have honestly watched my team shoot at enemies at almost point blank range, and stil they weren't hitting eachother, but that said, this doesn't happen very often, and usually the enemies and your team are very capable fighters.
The Good: Split screen coop is extremely fun and interestng. If you have a friend there's no reason for you to not play this game. The online game for it is also a must see, it is so interesting and fun. The whole coop competitive system of fragile alliance. This is definately a must try for anyone with online.
So, even though i loved this game i have to say that it is probably best to rent it first... but you should definately give it a try!