This is a fascinating discussion. I'm not really a RF user; I have a few that I've run film through but mainly for the novelty of them (FED-2, Bolsey B2, Bolsey C, Ricoh 500, something Olympus that is beautiful but really, really needs a CLA). Maybe it's heretical but I genuinely don't get the whole Leica religion; too expensive and I don't see a difference in image quality between one and the Zeiss lenses on my Contaflex IVs or even my Rolleiflex SLRs (yes, crappy camera, but those lenses!). I've only once ever had an issue with shutter noise and that was shooting a wedding in a CofE church in Lincolnshire, England some years ago when the priest had a fit about the noise of the shutter on our DSLRs.
Maybe it's not technically a "real" rangefinder, but lately I've been playing around with shooting my 2 1/4 x 3 1/4 Speed Graphic handheld using the Kalart RF and 120/220 rollfilm backs. It's an adventure, really, because small and easily portable it's not (though lenses tend to be a little smaller than an SLR lens). It's damn near impossible to see through the top viewport, so I end up focusing it with the RF up to my left eye to focus, then use the viewfinder on top to frame, then shoot. I have gotten some shots I really quite like and some that were somewhere south of good, but the challenge of using that camera keeps bringing me back to using it. It's just fun, and it starts a lot of very interesting conversations when I walk around town with it.