I have been using the 35f2.8 on one M2 body and the 35f1.4 on another. Low light situation, I just switch the bodies around (indoors, night time etc).
The 35f2.8 is nice! Very sharp but not too contrasty. Smooth mid tones and it is small and compact. Summer has arrived here (at last) so it is always along during the day. Perfect set up for a M2. For some reason I havent used it on a ZI yet, but with this sunny weather there are a handful of rools of Efke 25 calling to my attention and an appropriate reason for using them. The 35f2.8 might just be it.