I've taken 101 (Curtis) and 201 (Delaney) at UCB, both were very good.
Not to scare you off of it, but it's not everyone's cup of tea. You'll be writing (and rewriting) out of class. You'll spend 15-20 minutes on your sketch and the rest of the class talking about everyone else's sketches. In both my classes, we started out with 16 and dropped 2 or 3 people by week 3. It isn't like an improv class, where you can just show up and have a blast. That said, if you want to do it, the UCB classes were great.
VVV Eh, maybe 14 or 12. We did have a few dropouts in both classes though.