Bianca was pretty terrible because she was just a talking running gag. A really shitty one too because everything she did (and repeated) was annoying as hell. Oh and she manages to beat Trip despite being an utterly atrocious trainer in literally every other episode.
Then Trip because of all the shit in the massive wall of text I posted in the Trip thread a few days ago. Not bringing all that up again.
Finally, Stephan was pretty cool, had neat pokemon and also Sawk's Bulk Up animation was one of the best things to happen in Best Wishes because fuck, it was amazing and hilarious and amazing and I liked it