For years, I used a Mamiya RB67 for my studio portraiture work.  They always worked, a lot of options with lenses, screens, finders, etc.  Though heavy, I've used them hand held when my Mamiya 645 bellied up at a wedding.  It and my C330f saved the day.  About 10 years ago, I parted ways with it, along with most of my film equipment.
In the past couple of years, I've started shooting film again, and I've accumulated a number of different cameras, including a Cambo 4x5, Super Graphic, Mamiya C330s, and a Mamiya 645 Pro TL.  Only missing was a 6x7.  I wanted a RB67 Pro SD.  A local dealer had one, and I almost pulled the trigger, until he showed me a mint RZ67 Pro that had a WL finder and a 90mm f3.5 lens.  The attraction of the electronic shutter, and single cocking/film advance lever was just too enticing.  Now I'm a RZ67 owner, and I found an AE finder last night on eBay.  Can't wait to get it into the rotation.
The same dealer also had a mint condition 6x7 "23" Graphic back for my Super Graphic, and 3 BNIB Riteway 4x5 holders.