I got this lens about a couple of months ago. I use it with Canon 20D and it works perfect. I have had no problems. I used to take pictures at a dance party. The lights were down and only rotating colored lights were spinning. I was amazed that this lens not only focused fast but very accurate and sharp.
I was thinking about getting the f2.8 version, but didnt because the price is too high for my range, plus, on 20D you can crank up the ISO and get very nice images.
I love it.