I have the Mamiya 7 II and the Fuji III. Both are great cameras. I do shoot the Mamiya much more than the Fuji however. It is more portable and has the built in meter. But mainly because of the interchangeable lenses. For travel, the camera is terrific. I can fit one body and three lenses in a small shoulder bag.
I guess I've never had a problem with the internal meter on the Mamiya. I tested it with my film/developer combination and adjusted to get the correct exposure.
The Fuji is a great camera, and I shoot it when I want the 6x9 ratio. Great lens. Yes, it is big, but not overly bothersome.
They are both good, so weigh the strengths and weaknesses of each to decide which would be best for our shooting style.