I bought this lens a few years ago for my 20D.
It has served me well as my main workhorse lens since.
My original copy had faulty focusing, I sent back and replacement was spot on. I can't really fault the lens, it produces sharp pictures and for a 2.8 zoom it's dirt cheap.
I have recently upgraded to a 5d and will probably upgrade my main lens to the Canon 28-70 2.8 (resisting so far cause of weight/price) but I need that big red ring to give me credibility at weddings!