Better than my old G2 wide angle zoom for shooting exteriors and interiors of houses for my wife's real estate business. Reasonably sharp at 200-400 ISO in daylight. But in clubs, sharpness deteriorates at 1600 and 3200 with my D100 for concert acts.
Maybe this is because I shoot with spot focus rather than matrix focus. And it can be repaired with Neat Image reasonably well. Unsharp mask doesnt do much good.
Wish I knew why this is, since most reports call it a sharp lens.
Distortion is negligible, and only gets worse when I fix it with Panotool lens curve.