Everybody has different tastes in personality but given that Astarion is a high elf noble, vampire rogue. His personality fits his background. He is very useful in combat specially with his vampire bite that he gets after you allow him to drink your blood. 100% effective every time . I personally don't like Lae'zel's personality. I think she's a b**ch, lol, but I keep her because she's the only warrior companion, as I always play a magic type character.