I picked this lens up last week to and shot a horse show with it. For the first time I was able to use this lens for shots all the way across the ring and close-up candid shots outside the ring. It's really a fun lens to shoot with since focal length is nearly a non-issue and you get good shots the whole way through the range.
Others have commented on the image quality, and honestly I'm not the best person to ask about it since my 300D is a few steps behind what most others are shooting with. But it's certainly among the best of the non-L zooms.
The build quality is very good - all metal casing with nice tactile rubber grips. The zoom control is smooth, although I feel a slight change in resistance when I zoom through 200mm. The build is certainly among the best for any zoom at this price range. The autofocus is snappy fast and pretty quiet. After post-processing my weekend's shots I've found a very high keeper rate, which is very reassuring since my 300D is not known for having a sharp AF system.
Of course, the downer with this lens is max aperture - you don't get the light collection of shorter zooms. Plus you should stop down a bit to maximize the sharpness.
Here's the rundown:
So bokeh is kind of a non-issue and shooting action at dusk or under the lights is out of the question.
Overall, this lens is the perfect solution for someone who wants to upgrade the kits lens on their XT, XTi, 20D, or 30D but doesn't want to collect lenses or carry around a bunch of gear. I don't mean this in a scoffish way - I categorize myself as a well-informed prosumer and I think this lens is perfect for many of my needs because I can shoot in just about any situation without carrying a bag of other lenses or a second camera body.
Don't overlook it.