I've also heard similar comments from other Canon users and yes, you would expect an expensive lens like yours to give trouble free performance for more than 4 years. I have some Sigma lenses and one thats over 14 years old which has always performed faultlessly, so if they can make reliable lenses you would expect other manufacturers to do the same. I do share your feelings on this and I feel that Canon could at least put this right as a good gesture and an apology in the interests of good customer relationships. All the best.
Originally Posted by pad
Humility is an endearing quality and gains many friends, whereas arrogance loses them. Mike, 2012