He needs magical items from you! How can you not hate him?!
I mean what is a person compared to a magical artifact, even if I have no real use for it??
Seriously though, I personally don't really like him because of his attitude. But considering the current situation I could work with him. Even if that means that I am forced to use him as a recycle bin for magical artifacts.
I have voted Astarion, because he is an undead Abomination, which most my characters loath. Only a few evil characters of mine have necromantic leanings. And I have voted for Lae'Zel. My nicer/goodish characters dislike her agressive and hostile targets - and her being a loyal soldier of an evil empire. My evil characters will not take her, because she is more loyal to her queen than to anything else and will be of no help should they clash. Which is likely because the events of the prologue.
Minthara is someone I have not voted actually, because I have a hard time "counting" her. My good characters will (technically) not reject her, since to them she is just an antagonist. And my evil characters may be intrigued by her.