Thanks everyone for the responses. Seems like quite a few of you like the 135mm focal length. I really have no complaints using the 150 from an image quality perspective. It's just kind of a pain having the enlarger head up so high and the bellows nearly fully extended to focus. So I was thinking a shorter focal length would be nice - as long as it doesn't cause me noticeable falloff issues (which obviously are not currently a problem with the 150). I thought maybe the 120 would be nice but not sure. On the other hand maybe I should just follow my own advice and leave well enough alone.