In fact, the lens is also eligible with
Sigma's MC-11 converter, which means that 70-200S behaves better on a Sony body than any other non-Sony telephoto that I've used. It works fairly close to a native lens, which I certainly can't say for the Tamron or Canon 70-200mm lenses that I've tested on it in the past.
...
In the past I've frequently criticized Sigma lenses for inconsistent autofocus accuracy, but fortunately that has really changed in the past year. I've reviewed about 5-6 straight Sigma lenses that have shown markedly improved autofocus accuracy, and that includes the 70-200S.