Is the Canon EF-S 10-22mm f/3.5-4.5 USM Lens sharp? This page visually answers that question. Shown above are 100% crops from a lab-captured 14mm f/4.5 test image. Observe the contrast and resolution of these results.
Is the Canon EF-S 10-22mm f/3.5-4.5 USM Lens set to 14mm f/4.5 sharper than the Tokina 11-16mm f/2.8 AT-X Pro DX Lens set to 15mm f/5.6? The image quality comparison above also answers that question. Switch between the results to see the sharpness differences between these lenses.