Roger and Aaron at LensRentals.com have tested the resolution on a small batch of the new Canon EF 35 f/2 IS lens.
The lens performed better than the EF 35 f/2 that it was replacing, especially noticeable in the corners. While center resolution remains about the same. They compared the lens against the original EF 35 f/2, the EF 35 f/1.4L, and Sigma 35 f/1.4.
The real winner here appears to be the Sigma 35 f/1.4. Canon is going to have to make their sharpest wide angle prime ever to outdo the Sigma. It just happens that Norman Camera has the Sigma 35 f/1.4 in stock for $899.
I’m afraid this is a rather dull and boring post that doesn’t tell you anything you probably hadn’t already assumed. If you like to shoot 35mm and need Image Stabilization for the type of shooting you do, this will be a very nice lens and worth the money. Otherwise, you’re probably better off with something else.