Upload & Sell: On
There are too many reports of erratic AF with the Sigma 50mm f/1.4 for me to be excited about it, it has a beautiful rendering style for portraits though IMO.
In terms of autofocus, my Sigma 50 is one of the most reliable lenses I have. It's on par with the Nikon 60 2.8 Micro in terms of hit rate and accuracy.
Interestingly enough, the Sigma 24 1.8 is probably the least reliable, and my Tokina 50-135 are the 2nd least reliable.