Not to rain on the parade, but it was in to fix the IS fault that develops (I've heard some others have a similar issue, but not sure exactly how wide spread).
I bought mine two years ago, and discovered the dust issue since. Had it cleaned under warranty and then slapped a UV filter, which stops 99% of those issues (but if I ever take it off, it can get dust inside within minutes). I started cleaning it myself, until I managed to strip one of the screws holding it in place, requiring a service (and had it cleaned while it was in). But it came back with a Autofocus drive fault, so eventually it went back (at my cost). Then the IS start 'shunting' in the viewfinder, and generally acting up, so back it went (again at my cost). I tried to have the loose zoom ring fixed too, but they didn't seem to do anything about it.
It's the lens I hate to love. It's build leaves a lot to be desired, but the pictures and versatility are great. Just keep an eye out for the IS and the dust.
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