I did as you recommended, I have a Mamiya 645, first edition with the sekor c 80mm 2.8 N version, with WLF.
Today I went to a park as usual and and I took the Mamiya 645 and the Nettar 518/16.
-Mamiya and Nettar can be managed with wool mittens.
-Battery holds fine -15 degrees (Mamiya)
-Super bright viewfinder. (Big one with Mamiya, small with Nettar)
-Accurate focusing with Mamiya, zone focusing with Nettar.
-Chance to get wider lenses (Mamiya)
Cons - Mamiya:
-Small negative.-Not good for portraits mode (vertical composition)
this quits me chances of doing pics and I really don't like to be limited.
Cons - Nettar:
Feel free to add more cons or pros
Tomorrow I will get the results, lets see if I read correctly the light... It was sunny/cloud + snow everywhere.