>>3650272>needing to calibrate a brand new lensThis isn't really true. You *can* calibrate them, you don't *need* to calibrate them. It's an extra feature, and useful if your rangefinder mechanism is itself a little off calibration--you can just update your lens to match it instead of having to pay a bunch of money for a Leica CLA.
I've got the 7artisans 50/1.1, 35/2, and 28/1.4 for my Leica. I've been pretty happy with all of them and haven't noticed any serious image quality issues.