I can personally attest to the tank like build and dead-bolts reliability of an RB67. Doubles as blunt weapon - or more like battering ram, actually. You can step on it to get to a really high shelf. I think it gets Hassy owners so worked up because most people think its just a really big Hasselblad, which is not fair - and no one with a Mamiya should get that kind of attention! They don't deserve it! They simply did not spend enough! :)
They "don't fix as well" as Hassys because they... well, don't break as well. They are pretty much immune to all the little quirks that can send your Hassy to the shop in a jiffy if you're not careful.
As far as the inferiority of their lenses... I don't know off hand how many Sports Illustrated swimsuit issue covers were done on a RB67 - but I am willing to bet it was a vast majority in the last decade and a half or more - they seem nicely saturated to me. And I think people with those kinds of gigs can easily afford any equipment they want... so... some get Hassys, some get RB's and RZ's... obviously, it is not a matter of quality.
You will have a camera that gives you a big 6x7 negative and has a rotating film back - so no flipping of equipment necessary. Yes, it is big, and yes, it is heavy - by camera standards. Its not a car or a boat. If you whine about how heavy it is and you do not have a physical disability or extremely advanced age as an excuse... well, you should hit the gym. Maybe not the camera you want to take on a very long hike in the mountains - but I know people who do all the time. And they have no hunch backs - just nice pictures - to show for their trouble :)
And the bellows are great!
Oh, and this just in - I just saw one close on eBay (with a 90mm lens and one back, waist level finder) for $350 Canadian. Thats... $7.25 US or something:)
PS - You will always have your TLR if you feel inclined to travel really light.