I have owned about 5 or 6 Hexar RF, and a couple of the AF, over the past dozen years. They all worked great. Of course, everything can fail, and will eventually. But it's possible to buy two Hexar RF for one M6 nowadays; when the gap is that large, it's very reasonable to go with the Hexar.
I loved my Zeiss Ikon, but they are selling for similar dollars as the M6, but not as much as the M7.