I had the Canon 17-40 and loved it but just needed more zoom for my main lens, that is why i decided on this one. It still gets wide enough but can zoom almost 3 times as far. Great lens, like any Canon L series lens will be.
Consistent Output; Durable; Easily Interchangeable; Fast / accurate auto-focus; Lightweight; Rugged; Strong Construction
Lens Creep; Loud IS