The Tamron 10-24mm ultrawide has been on the radar for most shooters looking for a cheap wideangle lens so this review over at DPReview.com should provide helpful. For the money you pay, this lens is certainly a good one. A good buy.
Tamron has just announced the Tamron SP AF 10–24mm f/3.5-4.5 Di II LD Aspherical (IF), a new ultrawide that should supersede the slower Tamron SP AF11–18mm F/4.5-5.6 Di-II LD Aspherical (IF) which they’ve offered as a wide–angle alternative for Canon and Nikon shooters for a while now.
The range for this ultrawide is better than similar offerings and is even better than the Canon EF–S 10–22 mm, one of the better ultrawide lenses for APS–C cameras. It also shares the same max aperture throughout the range, putting it in direct competition with the Canon lens. If it sells for much less than the Canon 10–22, the Tamron 10–24 should be a good seller especially if it inherits the excellent optical qualities of Tamron’s 28–75 and 17–50 f/2.8 zooms.