Have one, love it, happy to sell though coz finances etc.
These are all 15 or so years old - so the occasional issue not too surprising but really, most are still running fine. Mine has/is.
Hexar RF is quite a different camera to the AF Hexar.
CLE - more problematic now, mostly due to being older.
Bessas - the mechanical ones are fairly straightforward, don't know enough about the electronic ones.
The "problem" really is that they aren't Leicas, so the cost of repair is considered "too much" - really you will lose more money walking out of a Leica shop holding a camera than you will owning a Hexar RF even if you have to bin the Hexar and buy another.
Of the three camera mentioned (and I've owned all), only the CLE has given me any issues - and that is resolvable without professional intervention, for now.