Lens repair/failure rates
 

http://www.lensrentals.com/news/2009...repair-data-35

I thought this would be useful to some of you.

aarrgghh i was just going to get the 17-55 IS USM =(
how do you tell if you have IS failure, AF electronics, or ERR99?

Err99 will show up in the display. It's a communications error. When I got it, I took off the lens, cleaned the contacts, and put the lens back on. It seemed to work again. I think about a month after that, it finally died.

You can tell when you have IS failure when you have IS on, and you try to focus on something. You'll hear the IS try to kick in, and it will constantly vibrate the entire time until you let go of the button. I found it seems to happen more on the long end and less likely to happen on the wide end.

You can turn IS off and the lens will work. (without IS of course)

Canon fixed it for only the cost of parts (which was $106 CDN) since my lens was out of warranty. They list of parts they used was "Image Stabilizer Assembly" and "Lens Assembly, 3rd Group"