The lens has a great zoom range, and takes nice clean, sharp pictures thanks to the image stabilization.  However, the auto-focus doesn't work all that well if the lighting isn't perfect.  Given a nice sunny day, the auto-focus is very responsive and accurate.  If you're indoors, or shooting at dusk, be prepared to wait up to several seconds for the focus to be set; if it can acquire focus at all.  I find that if I am dealing with dim lit shots of a static subject, manual focus is much more effective.Upon the first use of this lens, I thought something was broken.  This is because the image stabilization makes a light grinding noise.  While the noise can be annoying while taking pictures, it can be catastrophic when recording a video.  Consider that the grinding noise is coming from a lens directly attached to the camera.  This grinding travels very well to the internal microphone, and is forever recorded with your video.As a side note: It would also be nice if Canon started putting their lens caps on leashes.  For those that don't like a dangling lens cap, they can remove it.  For those who like it, we wouldn't have to buy a new lens cap! 

Question: How is the lens?
Answer: If you 're indoors