Attached to a Canon EOS 5D MKII it ranks 4th overall and 2nd for wide-angle primes, just behind the Sigma 35mm f/1.4 DG HSM A, which at a similar cost offers the same focal length, a wider f/1.4 maximum aperture but no Image Stabilization. You can read our DxOMark review of the Sigma 35mm f/1.4 DG HSM here.
A Sharpness Score of 17 P-Mpix for the Canon EF 35mm f/2 IS USM, compared to 15M-Pix for its predecessor, is an improvement of +15% and crucially it performs much better in the corners of the frame, which was the weakest aspect of the original. It’s not the widest Canon prime available with the Canon EF 24mm f/2.8 IS USM and Canon EF 28mm f/2.8 IS USM available at a similar price point and although they don’t quite achieve the dizzying heights of the 35mm they put in a very good performance, too.
At around the $800 - $849 mark however all three lenses are expensive but there aren’t any cheaper alternatives available unless you’re prepared to live with the relatively poor Sharpness of its predecessor the $349 Canon EF 35mm f/2. If you want the ‘fast’ f/2 maximum aperture and desire top-quality edge-to-edge from a Canon wide-angle prime you won’t go far wrong with the Canon EF 35mm f/2 IS USM.