this guy has some real-world samples of the 35mm f/2 IS:
http://eyvindness.zenfolio.com/35mmf2isusm/h4ed589de#h4f0f869e
I do see the slight ringing effect in the bokeh but overall it looks good. I'm also annoyed by the fact that the reviewer in this video can't get his stops right ... he even refers to the lens as an f/2.8 at one point.
need to see some head-to-heads between this lens and the Sigma 35mm f/1.4 before we can determine which one has the better overall image quality. I'm fairly sure that sharpness will favor the Sigma, but I'm not so sure about other things. and I know it's a niche usage, but I really wish some of the reviewers would take a look and see how the coma and astigmatism on these lenses are.