I wrote a review very positive some weeks ago on Fred Miranda, but i have to add a remark, ad you guess what about... About dust inside ! I don't want to rewrite my review, and I agree in all with the FM review of "perspective", so just add my experience about this dust vacuum cleaner... I never experienced that on a Canon lens, even the worses... Dust came inside after about two weeks of use in non-dusty (at all) conditions. I prefer not imagine what it will happen in dusty conditions. It is clear now with all the reviews on this problem that it is not because of a bad copy. It is a problem of conception and sealing. Some people said imprudently there is no difference with the L lenses, sorry, but for sure, here, there is. Don't send it back to the seller for an exchange, you will get exacly the same problem with the new copy. There is no only dust, but it seems little withe artifacts too on the internal lens. I showed the lens at the Canon agreed repair store in Paris (Vilma) and for them, "it is not a problem"... because we can't see the dust on the pictures... Not covered by the guarantee, and 80 USD for clean that with 2 weeks of immobilisation... Incredible... an unacceptable for a lens at this price. It is a real and very serious problem, and my conclusions are for sure as "perspective" says, Canon has to re-engineer and fix this problem, so it will take time, not sure of the results, and no other solution in this range if you need a Canon quality image, and the IS. Canon must give an answer and some explanations to the customers about that, if they don't want to see the selling curves of this zoom coming down very fast, and managing the bad feedbacks of the customers. for the moment, I keep it, because I need all the other features, and I am satisfied with the image quality. Real a great confort in walkaround ad reportage use, outside and inside. pics and samples of my first review (completed) are here on Pbase : http://www.pbase.com/isogood/canon_17_55 I don't shoot the dust, you know what it is. I know we are the first buyers of this zoom (I waited for a long time) and like we said in french we must "essuyer les plâtres", that's to say, be beta- testers, and discover the problems in daly use. So we take a risk, and we know that, we have to assume it, but Canon must assume too and give an answer, or at least, offer a free first cleaning for the first buyers.