The R3A with a 40mm Nokton is the first "serious" rangefinder I ever purchased. I can safely tell you that I never once regretted buying it and I still use both of them often to this day. The metering is accurate, the Nokton has a nice look to it, and the camera itself is rugged enough for every day use.
I actually think the Nokton is particular is a great buy. It's pretty dang fast at f/1.4 and it's relatively sharp. More importantly it has nice character. I would take it over the vast majority of modern lenses out there from the likes of Canon, Nikon, etc. I shoot with it around f/2 most of the time.
The only downside I can think of is that this camera is what started my obsession with M-Mount and Screw Mount lenses...which is not a cheap obsession to have. hahaha.