I'm pretty much set on not getting the new 35/1.4. The main reason is that it's too big. I use 35mm as a walkaround focal length and having a massive 35mm lens does not make much sense to me. I'm also very happy with the old version that I have. Finally, I'm considering another 35mm f/1.4 lens - the new version Leica 35/1.4 Summilux ASPH for my M9. The rendering while not Zeiss-like is really gorgeous. It's size, well:
(Leica 35/1.4 on the left and new Zeiss 35/1.4 on the right)
In terms of raw optical performance the Leica will probably run circles around the Zeiss. The only real disadvantage of the Leica is the price. Around €4,000 ($5,000), ouch.