I've had this lens for years and made many great images with it. Really, it has served me quite well.
However, I've had it repaired by Canon 3 times and it's never been in perfect working condition since the first time I sent it in. The focus has always been, well, chalky is how I'd put it. Not smooth at all. The slightest drop of this lens renders it inoperable and in need of being sent in for another sub-par and expensive repair and now it has broken again and is super slow to focus.
If I could do it again, considering how much I've had to pay to repair it, I might just save for the L.
The main repair guy at a very reputable local camera store here in L.A. told me this is the Canon product with the most repair requests that they've never issued a formal recall or notice for that would have Canon repair it for free. In other words, it's built poorly, Canon knows it, but won't do anything about it.