This question comes up on other websites too. I have an 85/2 AI and I like it. By the time of the 85/2 I think more people could afford such a lens. There just aren't that many 85/1.8s around. The ones I see are very expensive. The difference between 85 and 100 or 85 and 105 is not that great and I prefer shooting portraits with a 100 or 105. I also don't like shooting portraits with a lens as fast as f/2 or f/1.8 wide open. For these reasons I will reach for the 85/2 mostly when I need the extra speed and when I'm not shooting in the close range. I think both versions of the 105/2.5 are excellent for portraits. For Canon I have an 85/1.8 New FD as well as an 85/1.8 FL. I especially like the FL lens. For Konica I prefer the 85/1.8 Hexanon to the 100/2.8 Hexanon. My favorite 100s include the 100/2.8 Canon FD SSC, 100/2.8 Canon New FD, Minolta 100/2.5 MC Rokkor and 100/2.8 Zuiko.