Canon EF-S 15-85mm f/3.5-5.6 IS USM vs L-lens

I agree the 15-85 is up there with the L zooms in IQ terms. It wont match the new 24-70II or an L prime at the same apertures but there's no better lens with a similar range for crop. For 1.6 crop, for a general purpose zoom its this or the 17-55IS IMO.