I'm in the same hunt!  I borrowed a Mamiya 7 (not the II) from a friend of mine, and was amazed at the clarity of the negatives.  He had an 80 lens on it, which is the standard lens.  My only objection to the camera at all was that I wished it had a wider lens on, like the 50 or the 65.  I really like a wide angle lens, so if I ever buy one of these I'll want that setup.  Using my friends camera I found myself continually backing up for my shots, which I never experienced shooting with a Nikon 20mm wide, but the camera itself is great, the RF patch is bright and easy to use, even in low light, the meter was right on the money, without any need to bracket - at least for the 2 test rolls I shot in it - so I'd definitely give it positive marks.  
But I still like the idea of the Mamiya 6, since I've become accustomed to a square format after using my Hasselblad, Yashica-Mat, and Holgas.  However, since they are no longer manufactured (you can still buy a brand new 7 II with 4 available lenses) I might go with that perfect 6x7 aspect ratio.  Buying a new one would probably require that I sell a kidney or two, so I've been scouring E-Bay as well.  Haven't pulled the trigger, but I'm starting to weaken!  I hope to have one by summer, but Aline, if you get yours first, please let us know how you like it.  From my limited experience I certainly would love to have one in my bag!
Info Red
My wife, bless her beautiful heart, just asked what I was doing.  I told her I was posting this stuff about the Mamiya 7, which prompted her to say  "Just do it.  Just go ahead and order the new one.  You know it's what you want.  What do you work for if you can't occasionally spend some of the money on the things you want?!"
There might be a new 7II in my future sooner than I planned!
Bless her beautiful heart!  My kidneys are safe!
IR