Hold on. Did you just say his art were actually Kitsch? XD
Well, I was trying to be polite.
Seriously, though, Sweet's human figures were not very good, and I can't recall a cover of his that didn't contain at least one of them. Most of the other cover artists operating at about the same time were better: Vicent Di Fate, Bob Eggleton, etc. (and Michael Whelan, who's pretty much in a class of his own and has won a ridiculous number of awards).
