DAG has a fine reputation for his work, is certainly competent to overhaul your camera, and seems to have the best availability of replacement parts, particularly mirrors and prisms. John Maddox, a Leica screw mount specialist, seems to be as highly though of as DAG. Sherry Krauter doesn't wok on Barnack Leicas.
I would avoid Kindermann in Ontario if you live outside of Canada. The way they ship completed work, you will wind up paying a $30 customs brokerage fee to UPS (for a shipment which has no customs duty) in order to get your own camera back. I've also had problems with the quality of their work.
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