sigma 85 1.4 vs nikon 85 1.8g

[jamiebonline]

hi everyone

i know these are quite different but i need to make a decision for my d7000 and i cant afford the nikon 85 1.4

so its the sigma 1.4 or cheaper nikon 1.8g
i tend to avoid secondhand glass.

i heard that the sigma has af issues too.
i shoot potraits mostly and i currently have a 50mm 1.8g which i find too wide and dont like the distortion on headshots

thanks