considering buying a sigma...any feedback?

Hi everyone, I am looking for something to replace the standard kit lens that cam with my 20D. I am on a tight budget and am considering the Sigma 28-105 F2.8-F4 DG for 209 US Dollars, or possibly the Sigma 24-135 F2.8- F4.5 DG for 339 UD Dollars. I need a good wlaking around lens that will give me some added flexability in poor lighting conditions and a decent range of focal length.

Has any here tried these lenses? Are they decent?

I have the 24-70 2.8 and I love it. Sometimes 24 isn't wide enough for my tastes but it's not the lens' fault. I used to use it on my film camera and I got used to the field-of-view at 24mm, but the 20D doesn't go that wide. If you never used such a lens on a full-frame camera (film or otherwise) you won't care. Still, I'm very happy with the Sigma and wouldn't hesitate to buy their lenses again. Well built and significantly less expensive than the Canon versions.

The 24-70 2.8 DG EX Macro is a very good lens that will also do you well when light reduces.