Just to have another way to discuss companions, here are my first impressions that will affect any considerations about whether or not to keep them:

Lae'zel:
Considers me a lesser being and servant - so probably expendable. I hate this, but she's too useful to dismiss so I'll keep her around. She hasn't actually done anything but better not follow any plans made by her. We'll see.

Shadowheart:
Hmm..mysterious. And interesting. Doesn't come across as a typical Sharran but what do I know of them? Overall not particularly impressive but personally actually quite nice, as opposed to most of the others. I wonder how she looks if she unbraids that impressive hair.

Gale:
I can't put my finger on it, but I don't trust this guy. And the way he made advances in camp was outright creepy. We knew each other for....one day? Thankfully I'm a sorcerer so I don't need to bring him along on my expeditions. Also, he managed to offend the goddess of magic so hard that she cut him off from the weave? Heh, I know a ton of obnoxious wizards, what must you do you merit that? Well, we're all together in the same problem, so I'll keep him around. We'll see.

Astarion:
Arrogant asshole, but most of it is just talk and I can't really blame him for anything specific except that, well, feeding attempt. And he promised not to do it again. Nonetheless, vampire spawn, one wonders if he's capable of keeping that promise. Better be careful around him but for now, too useful to dismiss. We'll see.

Wyll.
Another arrogant asshole. Great. It's also mostly just talk and he's not a vampire, so probably more trustworthy, but I don't like him. Maybe he'll get more bearable once he's free of that contract. We'll see.

Karlach:
Someone normal at last. Heh, did I really think that about a tiefling with a magical heart replacement? In any case, whatever else she is, that's one I'd trust at my side in a fight.

So, what are everyone else's impressions? In free, unsystematic terms?