One distinction of the Bronica ETR system was being the most affordable option with leaf shutter lenses, which some wedding and portrait people liked.
There are metered prism finders for it, like one on eBay right now for $110, but I know nothing about quality etc.
I have heard keh.com recommended as a good place to shop for second hand MF gear, at least to get an idea of prices and what accessories are still available