I picked up an RB67 Pro-S kit for <$200. So the price factor is in your favour for that. I have been shooting alongside a photographer friend of mine who is using a Bronica ETRS (a 645 SLR). We just did some 16x20 prints in the darkroom. There was a slight edge to the RB67 for sharpness I think because he used a diffraction-limiting aperture on the negative he was enlarging and I didn't. But the tonality and everything for the two was pretty awesome.
We've been scanning with the glass carrier in a Nikon Super CoolScan 9000ED and the differences between the negatives is there, it just depends on how large you need to print or crop. I'd say look at the kind of system you want to use (different types of finders? replaceable backs?) and the lens lineup you would like.
I would say the RB67 lenses are a bit slow, and I'm jealous when my friend can shoot at f/2.8.