I also don't know how he is on TV, but I will say that I don't care for him as much on the radio when Greg Gania is sitting in for Dan. his business/party needle definitely seemed to swing toward 'party' the one time I heard that combo.
ETA: I don't mean to imply that Andy is 100% responsible for the atmosphere when Gania is there. Gania seems to bring at least as much of that as Dirks does.