Comments about Mamiya Mamiya RZ67 Bracket f/100-200:

If you have the lens, it's a very, very good idea to use this bracket. The 100-200 is expensive and nose-heavy, and it's not worth the risk of damaging it by hanging it on the camera without the bracket, exposing the mount to all that torque. I've heard a few complaints about alignment being off to the point where the bracket doesn't support the lens, but I haven't had a problem with mine.

A good, solid piece of metal. The only down side is portability - it takes up a good chunk of space in the camera bag. But then, so does the lens - some choices require concessions to be made.