I totally agree with the above. Right now Leica prices are rather stable, maybe even going up a little, so if you have the money to buy one I say go for it. If you decide it has no real advantage or if you just simply don't like it you can always sell it and get your money back provided you don't totally bang it up.
For my part, I own a Bessa R3A, an M3, and a digital M9 (we won't talk about that last one...)
I admit I tend to take the Bessa out more than the Leica M3 for a variety of reasons:
1) I like the 40mm focal length when just photographing random street scenes and the R3A has the frame lines for it. It's slightly wider than 50mm but not really "wide" if that makes any sense at all.
2) I don't care nearly as much about the Bessa getting beat up. If I'm traveling by plane and the airline looses my luggage I'm not going to flip out about the loss my Bessa. I can easily buy them brand new for cheap.
3) I find it easier to load film in the Bessa as it has your standard hinged back door.
That being said, overall I would say the Bessa is an inferior camera. I've had to adjust the rangefinder on mine several times as it seems to get out of wack pretty easy. Thankfully its easy to do yourself. I would also say the rangefinder length means you need to stick with wide-ish lenses. I attempted to use a 90mm on my R3A once and hardly any of it was in focus unless I stopped down to at least f/8.
I've never had any capability issues with my Bessa. I use both screw mount and M-mount lenses on it just fine.