Got to remember though that the 40mm 1.4 Nokton, while a little cheaper, has a bit of a harsher overall drawing style and even more of a jittery bokeh than the 35mm, which itself can be overly busy in many scenes.
Comes down to why your looking for a given lens. If its simply because you need more light gathering ability, then perhaps its worth the tradeoffs, however, if your also going after a certain overall way of rendering, sometimes the faster lens isn't always the better lens.
Counter intuitive to some, but sometimes a slower lens can actually have a much nicer way of rendering. Case in the ZM35 C vs the f2.0 version. One would assume that the faster lens would look better wide open, with its stop advantage but shooting them side by side, the f2.8 C version renders much smoother, with a better transition and actually gives "better" bokeh and subject isolation even though its slower.
At the same time though, in a lower light environment, and/or with a camera with limited high ISO abilities, the f2.0 can still prove the more useful lens. When I had my Leica M8.2, which is pretty poor at higher ISO's I actually used the f2.0 lens because 1 extra stop was really make it or break it in terms of ISO settings. On a camera like the NEX which is quite good at higher ISO, pushing the ISO a stop is less of an issue and one can use a f2.8 lens in many more situations.
Most any lens is going to be a tradeoff though. CV 35 1.2 being an exception I would say because its not only fast, but its also optically very very good. Perfect edge to edge sharpness yet also sharp wide open.
Does have its disadvantage though in being a bit big/heavy on a camera like the NEX and its $1200 (as new) price tag.
One might be best served to simply wait for the CZ 24mm f1.7 E mount lens though. Who knows it it will be a real bargin at $699 or if its going to be priced really high, perhaps $1299 ??
Should perfect quite well though, at least based upon the A mount 24mm, and have a manageable size/weight and of course the advantage of auto focus and I would expect zero color shift and only slight vingetting.