Image quality test results have been added to the Sigma 105mm f/1.4 DG HSM Art Lens page.
This is a fun lens. Very unique. What should it be compared to? I'll start you with this one:
Sigma 105mm vs. 85mm f/1.4 DG HSM Art Lens comparison
The Sigma 105mm f/1.4 DG HSM Art Lens is in short supply. Order quickly to find one in stock (or preorder) at B&H | Amazon | Adorama | WEX. Note that the Sony mount version is due later this year.
Rent the Sigma 105mm f/1.4 DG HSM Art Lens from Lensrentals.