Yeh in co-op you share money and XP, so even if you just stand on the spot you will rake it in...especially so if you're playing with someone a lot higher than you (I imagine someone who is level 50, killing just one boss would level you up almost instantly if you're level 9).
I'm currently level 43 and playing on the Torque DLC, finding it a lot more fun than the pirate one, although I'll go back to that after. Got some really good weapons now - although being a Gunzerker my best weapons seem to be snipers?!?
Hoping with the next DLC the level cap goes up to 60 as in my second playthrough I am yet to finish either DLC or the main story and hardly any of the side quests.
Add me on Live if you want, same goes for anyone else playing this little gem of a game!
Brando M83