Personally I was not a big fan of the the 35/1.4 or 1.2 VC lenses but if you think you'll need the speed they are certainly good lenses. I have a few 50/1.4 and 1.5 lenses, they are great for their purpose when needed but I shoot and prefer my 50/2.0 lenses much more.
I've read different stories about the 35 f1.4 some indications that at least some specimens are soft. I haven't as yet read anywhere someone bad mouthing the Zeiss 35 f2.8. On the contrary, most all have given it high accolades...even Ken Rockwell and that's saying a lot.