I was reading a Japaness magazine yesterday called "Leica Magazine", issue 10, and it has a comparison of 4 35mm Summicron, from the 8-Elements through to the current ASPH. Very subjectively, I think the 6 and 7 elements 35/2 have the best bokeh, with the 7 elements coming out slightly ahead.
The gradient of in-focus to out-focus (front and back) is important to me. ASPH failed quite misarably in this regards with its very steep focus fall-off. 10 meters or so, everything loses their forms and there seems to be a gaussian blur to the quality. 8 elements seems to do this well, but perhaps a little too well, resulting in a rather harsh look (and a little more "ni-sens" than others). The 6 and 7 elements is in the middle with the 7 element being a little smoother.
Another thing is how much contrast the oof areas have since they can rob the attention from the main subject. And again, the older lenses seems to be a little better.
The only good thing about the ASPH in terms of bokeh is how it render circular highlights. Very neutral.
In terms of other optical qualities, ASPH won out on sharpness in large aperture range. Contrast is also higher, but as a result, the "look" is also more clinical. In night shots for example, abberations are very well controlled in the ASPH, but if you're into mood, this may not be a good thing. For example, lights and skin don't glow at all... As a result, pictures with older version seems livelier and with nice character, particularly the 8-elements. Finally, flare control seems best with 6 and 7 elements. 8 elements is terrible in this regard and a slight hint is present in the ASPH (which I thought should be better)...
Considering the many points, 7-elements (and that's the touted "King") being the middle of almost everything, seems to be a good choice... It is also the smallest of the lot.