I've sent equipment to Leica NJ three times. The first time was a 50mm 2.8 Elmar M, for 6 bit coding. They had quoted $250, which I thought was a bit steep. However, when the lens came back they had adjusted the focusing action and cleaned the lens, which I did not expect, so I was satisfied with the service and cost. The next item was a Leica M9P, which had its sensor replaced under warranty at no cost. Both times, the turnaround service was reasonably prompt (within a month, if I recall correctly) and communication was excellent.
The third time, however, has me thinking. I just sent them my Leica M6TTL to replace a bent rewind crank, due to an impact. Other than the bent crank, it did not appear to have any additional damage. Yesterday, I received an estimate for the repair, which includes replacement of the first shutter curtain, alignment of the rangefinder, replacement of the vulcanite (not because it needed it, but because of the repair) and general CLA. The estimate is $690, which made me stop breathing for a second. I will probably go through with it because the camera is still worth more than the $690, but I am not happy about it.
Antonio