My only criticism is that he sometimes sing far too many words at too fast a rate that he's hard to understand which may turn new listeners off. If you read the lyrics and come to understand the songs you really appreciate them a hell of a lot more. ("C is for Lettuce" is a great example that could be easily dismissed if you don't get all of the fantastic words...)
Other great songs of his include "Frank's Not in the Band Anymore" (the tale of a terrible drummer who gets even worse with the gradual loss of each of his limbs... Very touching...), "Dear God" (the rantings of a chronic worrier), and one we can all relate to, "I Don't Give a Shit About Your Website".
Anyway, buy his stuff, he has a wife and son to feed.