I know that this is an aging thread but I will add my 2 cents. I have owned an RB67 system since July 1978 that is almost 42 years and I think that is is one of the best systems out there. Is it perfect? No! Is there something smaller and lighter? Maybe. I have gone to the trouble to weigh mine on a good scale and found that it was not that much heaver than anything else I checked. The pentacon 6 with a few lenses weighed more. So did a Bronica S2 with a few lenses. More versatile yes. All of the lenses use a 77mm filter except the 37mm and the 500mm. Take for example the backs they are interchangeable with my Horseman VH-R and vise versa. I also have a Mamiya press with the G back and it works with it. Would you like to have one of the best MF wide lenses on the market? The Mamiya press 50mm is it, just move your Mamiya RB67 back to it and shoot. How about shift lenses? The 65mm on the horseman and your Mamiya RB67 back have you covered. Macro? The built in bellows with the 127mm is about as good as it gets. The 140mm is better but most flea bay cameras come with a 127mm. I have had both the original 127mm and the new “C” lens and could not see any difference. Should have saved my money. The original 250mm is a sonar formula and if you like the sonar look, think early 105mm nikkor you will like it. It is slightly soft in portrait settings but that is ok. The newer “C” is an ernostar formula. It is sharper up close. I have both. Different horses for different courses. The 180mm is stellar. I have no idea why they changed it. I have only had 1 failure in all that time and that was the 180mm shutter. I had used it a lot in the studio, and I bought it used. I think that the repairman told me that the reason it failed was because it was used too much when it was new
There is a lot to like about the RB67 and as most system cameras go unless you commit to the system and buy into it you might as well use a fixed lens camera like a Yashica mat or Autocord. There is not much advantage to buying a body, back and 1 lens. Been there and done that. I hope I helped some one here.