I know I'm a little late coming to this topic, but to say that the RZ is not a professional-quality camera is so far off base as to be laughable. I'm sorry that the OP has had this negative experience, but it is not indicative of the camera system as a whole. I've been through a lot of equipment, especially given my age. In the last 12 years, for example, I've been through 5 Nikon F3 bodies and SEVEN Mamiya 645 bodies. 3 and 5 have failed, respectively. All were purchased used and while one or two failures were genuinely defective and were covered by warranty, the rest were just beaten into the ground from hard use. Now, do I think that either the Nikon F3 or the Mamiya 645 aren't professional-level cameras? Hardly! Why not? Because I understand why things fail sometimes and that I happened to be working the odds by buying ugly users because I was a poor student. I bought cheap and used them until they died. The two RB67s that I had for a while were even better and those absolutely refused to even whimper no matter how hard I used them.
My point is this: the occasional equipment failure can be devastating to whatever you happen to be working on at the time, but it does not necessarily indicate the quality of the tool you are using. On a long enough time scale, EVERYTHING will break down, and there are always flukes that show up early once in a while. The RZ67 is one of the best, most reliable, most bulletproof medium format cameras ever made, and it is a tool of the highest professional class. I'd take one over a Hasselblad for reliability any day of the week.