it used to be my streets lens, here's one to share
sigma 85 is the rival for c 85 1.2 ii and n 85 1.4 d/g, and even the zeiss, i find it unfair for it to be compared to c 85 1.8
sigma's 9 rounded blades are their traits in their premium lines (50, 85, 24-70 hsm [the new version]), bokeh is super smooth and very pleasing, and all are extremely sharp with very high hit rate in accuracy
here's one random with s 85
read up these reviews :
http://darwinwiggett.wordpress.com/2011/04/12/sigma-85mm-f1-4-vs-canon-85mm-f1-2l-ii/
http://hofferphotography.com/2010/11/16/my-sigma-85-f1-4-vs-canon-85l-review/
http://www.alanabramsphotography.com/2010/10/sigma-85mm1-4-ex-dg-hsm-lens-review-part-1/
there are many other sources out there for direct comparisons for the sigma 85 with c 85 1.2 ii, but if you've read the above enough, you'll understand which is the real deal
a grey c 85 ii costs 3k, i would have been happy to pay 4k for an s 85 instead, but no, they are only less than half of that, and that itself is unbelievable
the above was taken at an event last year with the c 85 1.2 ii but with a 1ds iii - focusing is two times slower, less accurate hit rate wide open, chroma is no better than s 85
keep in mind that a 5d doesnt have af tuning, using 3rd party lens on it may cause you headaches at times when af misses
but if you can afford the working space, a longer telephoto range (200mm and beyond) will be more ideal (my preference) for portraits