Got my 645E on Thursday -- a used mint model, still in the box for $475. I love it..great viewfinder, controls are easy to use, and so long as there are film inserts, the only reason I can think that someone would want removable backs is to use a digital back, anyway, or polaroid. I shot a test roll the same night and developed it -- no problems. I really like the aperture priority and the nice viewfinder with adjustable diopter!