I bought a factory refurb'ed M8 with a 1 year warranty and during that year the camera was away twice for sensor remapping due to hot pixel lines. As soon after it came out of warranty, I sent it in to have the rangefinder calibrated. Nothing else had happened to the camera, the RF was just off a bit. When I was told the estimate of just over $600USD for this I explained that all I needed was the RF calibrated and from Sherry K. that is less than $100 (but she doesn't work on digital Leicas, or didn't at the time.) Anyway, I talked them down to $480 and had to sell the camera just to pay for the service.
I also bought an M9, brand new and on the third day of ownership, it went back to Leica for remapping hot pixels and the annoying vertical lines. It was away almost three months. The better part of a year of trouble free operation then it had to go back and this time it got a new sensor. That was about three months away as well. Then I had a shutter fault in either late 2011 or early 2012 and the camera went away again, this time for a new shutter. All of this was under warranty and during the 20 months I owned the M9, it was away at Leica just one week shy of 10 months. So I had to get out from under that camera quick since I didn't want to pay an extra 300 Euro for a year of warranty when the track record of that body showed that I could be only shooting it 50% of that year. I sold the camera for quite a bit of cash and a Nikon SP in trade. I also needed a reliable tool, so it had to go.
The digital Leicas are fantastic when they work and work well. When all the headaches are gone, they are great. But the headaches are big ones and those, combined with Leica's customer service that certainly didn't treat me like I had bought their flagship camera from them brand new, convinced me that Leica will never get any more money from me.
Phil Forrest