Doug, that's really crappy news. As you know, I have a couple buddies that have sigma gear. About 50 % of this gear had to go back to the dealer to be replaced because they quit working properly after a short time, or didn't work properly right out of the box. One guy went through 2 flashes before he decide to go to Canon. Then his 70-200 died, and had to be replaced. He now is thinking about selling the new one to go for the Canon after he tried mine and realized it was considerably faster to focus. Now I don't mean to rag on Sigma gear, but my 420 flash probably has been fired more times than my buddies 4 sigma flashes put together.
Now on the other hand, my next lens purchase will most likely be the Sigma 24-70 f/2.8 macro. For $400, I'll take my chances.
So you finally heard about creds eh? Hope it works out.