I have the 110 f4.5 1:1 Macro, it's a great lens and focuses to infinity, so I assume it could work for portraits. The 150 is less money (and doesn't focus very close). I also have a 50, 65 and 80 (all PS series). If I were doing it again, I'd probably skip the 65, but I acquired it long before I encountered a 50.
I'd say the backs are the Achilles' heel, but the i series will tend to be newer. In any event, the problems (in my limited experience) are foam seals turning to goo. Jon Goodman/Interslice has a seal kit now, I believe. I redid one from one of his earlier generic kits, it wasn't a big deal.
I got a non-AE prism; mainly to be able to see when I have the camera up too high to peer into the WLF. I got a grip that was too cheap to say no, but I almost always work with a tripod for the Bronica.