If, like huiztgas, you'd like to avoid a 'clinical' look, the 35 Nokton 1.2 pairs nicely with a pre-ASPH 35 Summicron - ver. 1 or 4.
Like geesbert, I bought CV lenses experimentally, in order to see which focal lengths felt right on M8. (Hard to chose in the 24/5-28-35 range.) Then I replaced them with Leitz/Leica lenses, preferring the older & less contrasty pre-ASPH ones designed by Walter Mandler. When M9 arrives next week I'll be using 28-35-50, same as with film bodies.
Only for the 35mm focal length have I hung onto a CV. My choice among 35s is a Summicron ver. 1 (from an M2), & I rely heavily on it in daylight. It's not very sharp wide open, so i use the 1.2 Nokton in lower light. I wouldn't want to heft its bulk/weight the rest of the time.
In image quality my Nokton is moderately sharp wide open, doesn't suffer focus shift, & occasionally offers bokeh circles that look like little balloons with overly-defined outlines. My low-light work is mostly street photography where low contrast is helpful, & where vision & a 'decisive moment' tend to trump technical values. But I wouldn't choose the 1.2 Nokton for landscapes, urbanscapes, portraits, &/or general use. It's neither as smooth as a pre-ASPH Leitz/Leica lens, nor as crisp as a contemporary ASPH.
Kirk