[Leica] M6 question

[InfinityDT@aol.com]

With an upcoming venture to foreign lands, I was wondering, in regards to the 
M6, from those who have used them a lot over a period of time, how many 
people (if any) have had them fail in the course of use, and in what way? 
Later or earlier model?  I'm not referring to failures as a result of damage 
(impact, submersion, etc.) or things like the infamous frame-counter.  I'm 
concerned with something unforseen which rendered the camera unreliable or 
unusable, or spoiled film without your knowing it until developed...things of 
that nature.  (Like shutter, winding, rangefinder etc. but not "out of the 
box" defects).  (I know my description sounds complicated but I'm just trying 
to avoid a total rehash of what's probably been hashed here before.  Anyone 
can e-mail me privately, of course.)

Thanks
DT