I played splitscreen for the last couple of hours, and the only problem I experienced was that I was booted off the PSN about 1 1/2 hours in. Thing is, I get problem a lot with other games too, so I doubt it has anything to do with the game itself.
Anyway, I do like the game but find the constant enemy respawn a bit annoying. I went to do the blind cripple guy's mission (ol' whatshisface) and we had to run from the constant enemy spam. We were at only level 3-4, not skilled enough to just drop those dudes from a distance.
Fun game overall so far, well worth $40 Canadian. I like Claptrap. He's pretty funny, in an annoying way