Which one? The first or second version? I own the 24-70 2.8 (first version) and I only use it if I absolutely have to. I hate that lens. It is the one I always leave at home if I am shooting for myself. On the other hand, I recently had the updated version of the 24-70 2.8 from CPS, and I was completely blown away. It is sharp, the distortion is minimal, and so much faster than the first version. When I say fast; I mean FAST! It has a large price tag, ($2299.00) but in my opinion it is a much needed upgrade from Canon and long overdue.