Well to each his or her own concerning the prism, of course. I confess I've never used a TLR with a prism. My Yashica feels natural looking down, even held up to near eye level to look down and use the magnifier, which is really sort of "upper chest level," but trying to use the sports finder at eye level doesn't feel natural to me.
It seems more people print square or whichever fits than routinely crop to a rectangle. I'd say more of mine are square just because that's what I'm seeing on the gg so that's how I tend to compose it, but I have plenty I've cropped to rectangles too. With modern films even a 16x20 from a 645 portion of the frame looks great so I have no hesitation in doing so.