For me, the Hexar RF is the Leica rangefinder concept brought up to date - I much prefer using the Hexar to any Leica M. One nice little detail is the way the chamber between lens and film has a black velvet covering (rather than black paint) to reduce reflections to an absolute minimum.
I don't agree about the external finish of the Hexar RF being easily damaged. My camera is about 10 years old and still looks like new. The finish is much more hard-wearing than my chrome Leica M8, which has already picked up a few rub and shine marks.
Regarding registration, it's well-known that there are slight differences between the Hexar RF and lenses from manufacturers like Leica and Voightlander. I have used many Leica and Voightlander lenses on my Hexar, and - unless you're shooting wide open and close up - the slight registration error is not really that noticeable with most lenses most of the time.
The only time I really saw a serious error was with a Leica 50mm f1 Noctilux shot at full aperture. For best results, I would recommend you go for the Konica Hexanon lenses made for the Hexar RF - they are all superbly sharp, and the mechanical 'feel' is as good as (or even better!) than Leica. The focus is buttery-smooth and even, and (unlike Zeiss ZM lenses) there's no backlash or play.
Good as it is, I think £500 for a Hexar RF body is a bit high given the declining interest in film. If it was absolutely mint/boxed - well, maybe. But, I'd say around £350 is a more realistic price.
J M Hughes