Photozone review of new 15-85 vs old 17-85

I've noticed quite a lot of enthusiasm among owners of the new lens, especially commenting about the build quality.

I usually find Photozone's lens tests pretty reliable. They too said the build quality was much improved. However, optically it appears somewhat less impressive.

The Photozone test found that, at 50mm and 85mm, the old 17-85 was actually sharper.

At wide angle, the 15-85 is sharper than the 17-85 (just about every lens is), but with maybe even worse vignetting.

Has anybody done any careful side by side testing of the 15-85 vs the 17-85 to check on the accuracy of this finding?

http://www.photozone.de/canon-eos/465-canon_1585_3556is?start=1

http://www.photozone.de/canon-eos/402-canon_1785_456is_50d?start=1