With how heavily weighted we are towards 2D art, I'm surprised nobody's yet criticized PST's portraits. Much as I liked the game's aesthetic, the 3D art used in the bestiary and portraits was... unpleasant.
I've never played NWN2. Were the portraits in NWN2 like those in PST (3D and animated)?
If yes, then I'd definitely prefer 2D portraits like the ones in BG. They look better and if I don't find anything I like, I could easily switch to a custom portrait. I'm not really sure how custom portraits could work with 3D portraits.