Is the Tamron 70-210mm f/4 Di VC USD Lens sharp? This page visually answers that question. Shown above are 100% crops from a lab-captured 210mm f/4.0 test image. Observe the contrast and resolution of these results.
Is the Tamron 70-210mm f/4 Di VC USD Lens set to 210mm f/4.0 sharper than the Tamron 35-150mm f/2.8-4 Di VC OSD Lens set to 150mm f/4.0? The image quality comparison above also answers that question. Switch between the results to see the sharpness differences between these lenses.