Aspherical elements are no guarantee of anything in particular.
I really like the ZMs. I bought a 50/2 when it first came on the market and have followed it up over the years with the 21/2.8, 28/2.8 and 35/2. These, along with a Leitz 90/2.8 I seldom use, form my Leica M8.2 lens lineup. Leica could learn something from the way Zeiss has combined focus tabs (bumps actually) with ribbed focus rings. Nice handling. The lenses are all crisp & contrasty with clean, neutral color.
I don't really need the 35/1.4's extra speed but I'm curious about it just the same.
-Dave- (whose M6 kit features WWII-era Zeiss 35, 50 & 85mm LTM lenses)