I have the Voigtländer Color-Skopar 28mm f/3.5 lens, which I really love for film M-mount cameras but has some imaging issues on the M9 and A7, and the Ultron 28mm f/2, which only does "okay" on either film or digital cameras.
As a thought experiment, if one were to want a Leica 24 or 28 mm lens to replace the Ultron for use on the M9 or M(Type 240), which one would you go for of the following and why:
Summilux-M 24mm f/1.4
Elmarit-M 24mm f/2.8
Super Elmar-M 24mm f/3.8
Summicron-M 28mm f/2
Elmarit-M 28mm f/2.8
I don't know that I really want to buy another M lens at the moment, but if I'm going to keep the M9, I'd like a 24-28 mm lens that performed with fewer problems.