H*, no never really had the chance to take a FSU-built camera body out to play and in a way I must admit that I'm not terribly eager to. I keep hearing about the lacking quality control, having to send back cameras until you 'get a good one, etc, etc.
One of the things that I really like about the M3 is the very solid build. I really wanted a high quality, manual camera to compliment my Hasselblad. For some time I used the Olympus 35SP as just that but I must say that after having used the M3 for some months now there is no going back.
There's also no real 'need' for me to get one as I'm not a fan of multiple camera bodies with me at the same time.
Many people like the Kiev/Fed/Moska/Zorki-lines though and that's great I think.