I have to say that being old enough to had played the old BG games, I initially have confront feeelings about them. But after making a playthrough where I take both for the majority of act III. I really like how much content they have in the act (still want more) how it is. Almost every mission in act three have a moment for one of them, or both to interact and usually always in a cool way.
Can really tell why people usually forget them. Maybe it just because they are seen as nostalgic merchandise? (Myself was on that boat before trying them) Because they don't are a romance option? (that is a good thing for me. Not that i have anything againts romance and sex. All the oppositte! but the way every companion in this game try to jump on you is just annoying) Or simple because by the moment they show up you are use to your party and don't change it?
But taking them with me had rewarded some memorable moments. Best "conversation" till now in game for me is:
When you confront Sarevok and he recognized them and your character can awnser something among the line of: (sorry i don't play english so probably it isn't the exact quote) "You two want to kill the old man, or I should do it?" It's that baddass that I would have pay double the price I pay for the game just to have a voice character and being a proper scene
