The sharpness and color reproduction are great cinema in this class. The distortion and vignetting are over the entire range at a low absolute level and CA's must be really looking really good. IMHO the best thing that you currently find in this price range. I also had a short pleasure with the new Tamron 70-300mm some time ago. Is a very good part to fight price, though it does not serve up the Canon. Since you can now ponder the price difference, and ultimately this is clearly a very individual decision, but 80-100 euros surcharge for a better part for me were when buying this lens no basis for discussion. I think not only the optical performance of the Canon better, but the AF is significantly faster and all who use Canon Photo Professional and want to spend money on additional software must be said that one can eliminate the distortion, vignetting, and chromatic aberration in a few clicks without Surcharges for additional software.
What most people know for sure, though here again mentioned: Except for the Vollvormat racers, please include the crop factor with. Then you see the zoom range with different eyes. Simply crazy how close you can be far away things ranholen. In addition, you can do with the lens wonderful Macro recordings. Of course you have to keep a very respectable distance, but for certain motifs with wild animals and insects rather is specifically an advantage. Shaky hands at large focal lengths counters the very good image stabilization outstanding. It also helps one if necessary to save some glare levels.
In short, bombs Tele Shard!
Greetings.