He's pretty entertaining. I've seen him at DragonCon a couple of times, where he does is fanboy rap schtick. Some of the songs are a bit rough, but some of them are pretty freakin' amusing and he's been getting better over the years and has been branching out into other types of music. It's Dr. Demento parody fare, so if you're a fan of novelty songs and are tolerant of ultra-geeky white boy rapping, he's a lot of fun.
And, hey, he got John Kovalic to do his latest album cover, so that's pretty freakin' awesome.