Thanks very much for the helpful and informative replies, all. Sorry I'm late in replying, but here goes:...
Any other things on the Bronica strike you as being better compared to the Mamiya?
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I think all of the responses in this thread are painting a picture that you won't go wrong with either of the Bronica or Mamiya 645 packages. People love them both, and rightly so. Both have reputations for reliability, very-good-to-great glass, and can yield excellent negatives/chromes. The details between them are generally small, and it will come down to personal preference.
My preferences came down to feel/function in my hands, and the swappable backs. For the former, the ETRSi with a Speed Grip E feels like my manual Pentax Spotmatic on steroids. Not an original statement, but true. The thumb winder is in the same place, the shutter is tripped with the same finger at a similar angle, the body is balanced and the lens focused with my left hand the same way as with my Spotty. The transition was easy. Now, if I shot with a WLF as you have mentioned you might, I have a feeling that the grip might not provide the same advantage.
For the second point, an example. I wanted to experiment with Kodak 320 TXP in 220 pushed to EI800, just to see what it might look like. I loaded that roll 4+ months ago, firing off a few exposures every once in a while when I was in a low light scenario. I finally finished the roll this weekend, but have shot dozens of rolls of TXP, TMX, TMY, FP+, Portra etc. in other backs in the interim. That EI800-loaded back has been in the bag the whole time, ready just in case, and I never wasted any of the 30 exposures because it was going to be the wrong film for the task at hand.
So I won't say the Bronica is "better", because it's not. It's just better for me/my hands/my shooting style. But that 80/1.9 has always made my mouth water...