I've posted in the "Other" portion of the Mamiya section...
I've two Universal bodies (one "chrome", one black)
50mm lens
75mm lens (Polaroid capable image circle)
65mm lens (incredible, for only 4 elements!)
100mm f-2.8 (my standard film lens)
127mm lens (standard Polaroid lens)
150mm lens (unlike the nearly identical Tessar copy for the Polaroid 600SE, this one clips the corners on Polaroid)
I've had mechanical issues, but none critical. Parts of the camera setup have been to the shop (the 75mm lens is waiting for me as I type- shutter work) but honestly, it's been a good camera- takes good pictures.
I've one criticism and solution for it, though. It's hard to pack. Not "heavy" exactly, but simply very difficult for the odd shape to pack effectively. The backs are huge, and make it all the more difficult (though the Graflex backs make the camera slightly more packable). For travel, I bought a Mamiya 7 with a 80mm and 43mm lens (want badly the 150mm!) and suffer for the lack of flexibility compared with the Universal...
(Comicbook Store Guy from the Simpsons: "Favorite Camera Ever.")