I just played like an hour online and got dominated pretty hard. I'm only level five, so I don't really have any of the perks, which I think has a little to do with it, but still, the best I could do was 7-11.
Some of hit detection seems a bit off at times, for instance, I'll run right up behind someone with the shotgun, have it pointed directly at their torso, fire away, and it somehow misses. That coupled with the fact that it seems like you really have to lay into your opponent to kill them, it can make for some really frustrating moments.