Sometimes. I really like Madlib as a producer. He's one of the best hip hop producers, IMO. Quasimoto is his side project where he also raps... doing crazyness to the vocals. I think it's OK, from what I've heard.
Do you have the Madvillain album? I definitely recommend that. It's produced by Madlib with MF DOOM as the MC. There is also some Quasimoto on the record.