Sigma 105/ f2.8 EX vs Canon 70-200 f/4L USM
Switching to 20D brought problem with Sigma (Err99), so I had to have it re-chipped. Having upgaded to a new Canon body in the future I wouldn't like to have the same problem. Beside this the Sigma 70-200/ f2.8 is much havier than Canon. On the other hand, I shoot with Sigma and must tell the pictures were great.