I have an RB67 Pro and the negative size is a definite plus. That said I bought a Fujifilm GA646zi which produces 16 645 negatives on a roll. I also have two Mamiya 645's. I took the Fujifilm to Italy and carried it everywhere in my shoulder bag. Hand held it's like a 35mm, very ergonomic and functional. It's "normal" view is portrait since the roll loads from left to right.
It's a perfect format inbetween 35mm and 6x7. I can't see taking the RB and accessories on a trip like I did. If I were to step up it would be one of my 4x5's. The RB has its place no doubt, in the studio and out on location. Traveling and carrying it around though isn't for me.