Oh Brothers, our fellow Theo Sulphate has seen the light!!
Praise the Mamiya RB67, and the RZ too... for they are the saviors of medium format photographers, for they will reliably cope with very slow shutter speeds without any camera shake; for they offer you generously more picture area, for they will not seize and lock unexpectedly (Damn on those infidels who have not read the user manual.) Let's also praise the Sekor lenses, their designers never forgot that good sharpness needs to be partnered with beautiful bokeh.
Truly a gift from the heavens! Repent if you use the swedish clunky machines!! Go Mamiya!
{Currently own two RB67 + the 50, 90, 127, and 180 lenses}