Season one of Angel is easily the worse. It only gets better from there (the final season fucking rocks). The things they do to some of the characters is downright evil. Going back on Buffy I've noticed it hasn't aged all that well. It helps that the show was self aware of it's own campiness and drama. Even in the bad episodes of Buffy (and sometimes Angel) there are a couple of good lines/moments that would make me laugh.
Also, am I the only one that liked how dark the last season of Buffy got? Even with the shitty teen squad and lackluster finale there's some pretty cool moments throughout the season (Caleb's girl obsession, conversations with The First, Giles' outbursts, Buffy's nervous breakdown).