One minor point - some 645 cameras (Bronica, I think) get 16 shots on a roll but the Mamiya 645 gets 15, or at least my Pro does.

Hit rate may be better, maybe not. The metering in the AE Prism finder seems to be spot on, but it depends what you've been shooting. It isn't a matrix meter, not really. It does have spot, averaging, and a mix that works a bit like a primitive matrix mode. It does have exposure memory lock so I meter, lock (partial press on the release) and re-compose and shoot just like I do with my Richoh (can't with the LX which lacks this handy feature.) Focusing will be more critical too so that could be a bit slower. But the prism is fairly bright and it's pretty easy to focus IMO.

I THINK I was paying about $5-$6 a roll in the mid to late 80s. I started doing it myself for about $2 and it seems it was about half to one third the cost.