I have two F2AS. Both are still running perfectly and have never had any service whatsoever (actually, one of them just stopped syncing with flash, so I guess it should go in for service....but since I bought an 8x10 I haven't shot a frame on smaller format). My experience with Leica is that the collectors drive up prices beyond their value to me as a shooter (YMMV). Granted, my experience is with Leica-rangefinder gear, and the same may not be true for Leica-reflex gear.
While the original post said "excluding lenses", to me the point is the difference in the glass. I see a real difference between Leitz and Nikkor lenses. It's subtle, but it's discernable. When I look at the pictures I've done with Leica glass they're a little smoother, maybe a little less contrasty (I was using mostly 50's and 60's glass), with a special quality that I like. I like Nikon glass, too, but it seems snappier, less romantic. This may be complete BS and totally psychological, but it's my perception.