Halsin and Wyll have the personalities of wet dishrags, and Astarion is way over the top.
The others are all awesome, each in their own ways.
Whereas from my perspective, Gale, Astarion, and to a lesser extent Lae'zel (her case is...different) are just Huge Jerks Who Enjoy Being Huge Jerks. Halsin, Wyll, and Karlach are sincere, genuine, supportive people who want the best for others and actively avoid being or causing problems for others. I'd much, much rather have a team of people who have good hearts and try to make wise decisions than someone """interesting""" where 95% of their "interestingness" is "being rude, crappy, selfish, or hurtful".
Minthara and Lae'zel are harder to parse with this because of the radically different cultural backgrounds they come from. Minthara I can at least get along with more or less from the moment she joins the group, because even though she can be a real sick puppy, she is respectful and courteous and wants to be a productive member of the group. Lae'zel...it took me a while to realize that she's
scared, and that her fear response is to become a haughty, judgmental butthole. This doesn't excuse her awful behavior, but it does warrant patience and understanding, so that she can learn that she doesn't need to be afraid and can get along with us (perhaps even better than she did with her githyanki brethren...)
I would say that I have issues with Gale because he and I are too similar in the wrong ways, but the utter amoral ruthlessness he displays at several points is the real kicker. He's got a genteel shell, much like Minthara, but beneath it is someone who would genuinely do anything for power, even if it hurt people he loved and cared about. You
can very, very, very slowly drag him away from that and persuade him that there's a better way....but why would I
want to when there's three other people right there that don't need to be convinced?