Selon Photozone Canon EF 35mm f/2 - Test Report / Review en conclusion :

The Canon EF 35mm f/2 proved to be a decent lens with very good performance figures in all primary characteristics. There's a little quality penalty at its largest aperture setting where the resolution is a little on the soft side combined with relatively high vignetting but the peak performance at medium apertures is highly impressive. Mechanically the lens is a little outdated by now and Canon should really consider to upgrade the lens with a USM drive and especially a decent focus ring.