I'm not overly happy with my Sigma 24-70 IF EX DG APO because it takes a maximum micro adjustment of +20 to get it in focus (and it is still slightly out, if I could adjust it to +21 it would be perfect). Yet if Sigma starts releasing weather sealed excellent lenses at prices that match the previous generation of Canon L glass then I'll be buying their products instead of this new batch of Canon lenses. I need a few more lenses to fill out what I want to do professionally, so I'm in the market with a reason to buy.