I use this adapter a lot. It's very precise and works great.
In the case of the macros, I would go for the Mamiya.
I have tested them agains each other, and the Mamiya 120 macro is
clearly sharper than the best Hasselblad macro(120mm cfe).
I hate to admit this

. I am a great fan of the Hasselblad V lenses.
I have heard the new Mamiya 120ts has started to ship. This lens is
very expensive but is said to be even sharper than the 120 macro mf....
Henrik