Go for the RZ. The lenses are generally better, there's no analog to the 110/2.8 in the RB world. PLus the ULD 50 for the RZ is superb (regular 50 is quite nice too!). RZ: smaller, lighter, easier to use, better design, more modern, not much more $, and lenses and parts are easier to find than the RB equivalents (if they exist at all...). There's no downside to the RZ vs. RB, in my opinion. The only 2 I could even think of would be non-battery operation of RB (a non-issue, batteries last forever in the RZ and they are cheap and tiny), and the so-called 6x8 back on RB, which in reality is only 4mm wider than the RZ 6x7 back. (74 vs 70mm). but basically those are non-issues. Everything else favors the RZ.

-Ed