I love this lens. It is without question my favorite lens in my bag, above my two "L" lenses. The quality of the images is near equal to the L lenses I have (EF 24-105 f/4 L & EF 70-200 f/4L). What makes it my favorite is the effect of the wide angle image. It automatically creates a feeling of spaciousness and place. The only drawback to this lens in my mind is the distortion at 10mm.
If you have an EF-S mount and don't yet have a wide angle lens, I highly recommend this lens. It is not terribly expensive, compared to Canon L lenses, yet produces great results.