I picked it up today after testing it in the shop for a while. There seems to be a tiny bit of focus calibration issue, either with me and my technique, my M9, or with the lens. My other lenses tend to focus fine, but the Distagon has a very slight front focus issue, a bit like the Zeiss Sonnar 50mm at f1.5. As I'm used to dealing with this on the Sonnar, and the issue is only present at close focus distances like from 70-100cm, I can deal with it, especially as I got it for a really good price.
Comparing it with the output of my Voigtlander 35/1.4 v1 and 35/1.2 v1, I'm surprised at just how glowy the f1.2 Nokton is by comparison. The Distagon is super sharp at f1.4. The f1.4 Nokton is better, although it still has a glow that can be annoying. At f8, the Distagon is one of the sharpest lenses I've seen, with almost no distortion.!