I went from a Mamiya Press, to a couple of RB67s, and finally Hassy 500s of several varieties. I can't speak to commercial shooting, but the Hassy's were excellent for fine art work, and that's why they're all I have left of my MF equipment. Other than my two Rollei TLRs, that is.
Many of the finder issues were easily fixable by going to the later model screens, and/or adding a prism finder.
But, having said all that, what I really want is a square format digital TLR. Perhaps with a huge Foveon sensor. And a Schneider lens.