I have a 7 and it's been a great camera with outstanding optics and I've had no mechanical issues. I especially like the 43mm lens. However, I've found I much prefer the ergonomics and results I get from my Hasselblad, so the Mamiya is likely to be moving on to a new owner soon.
Kerik's post show that there is no right or wrong, only what works for you. I had exactly the opposite experience. I owned a Hasselblad for a couple of years but sold it after I started using the Mamiya 7. I liked the ergonomics and results I got from the Mamiya much better.
I guess the point is that recommendations on a web site are a great way to get many opinions, but you will have to judge what works best for you. If you can, try renting or borrowing whatever system you contemplate buying.