I have the Minolta/Sony (Alpha) mount version of this lens.
Overall performance is excellent, but it is uniformly soft at 10mm F4.
By F5.6 it's very good; another stop down and it is awesomely sharp.
Lens flare is well controlled throughout, especially for an ultrawide zoom.
Ultra-wide lenses often capture scenes with wider dynamic ranges
because light sources and dark shadows are both in the frame,
and a lot of lenses have minor flare issues that give the dark areas mild
color casts in such a case -- this lens seems to keep the full dynamic
range crisp and uncontaminated.