I've been using the lens along with my 300D for a few days now. Good people lens. On a 300D it's a 136mm - perfect for portraits.
When you use the wider apertures you have to make sure to focus on the eyes, else your pictures won't be useable. This is standard in all people photography, but with this lens it is even more important at f1.8 or other wider apertures. I find it to be sharp at f1.8 and do not experience any softness as reported by others - you will only experience it to be soft if you focused on the wrong point of your subject.
I can't find anything wrong with the optical quality, af focus speed or build quality. Money well spent.