I just picked one up used on saturday.
Since I love my summicron 50, but find the FOV of 66mm equivelent on the M8 too long, I borrowed an old screw mount Jupiter-12 35 f2.8 LTM to regain the 50 FOV.
Coming from that lens the nokton is excellent. Sure it is a bit soft wide open, but stopped down to the Jupiter-12s f2.8 it is already nicely sharp. I love the compact size, and the location and feel of the aperture and focus tabs. Great lens.