I can't help but wonder how Canon will price this. If it is priced the way Canon is going about the new lenses, I expect it to be in the range of $ 1,500 to $ 2,000 but then it will have to be substantially better than the Sigma's offering, which retails for less than $ 900.
Interesting times these, maybe Canon will be caught in a bind and the pricing will be "affordable" just because of existence of the Siggy
Canon will also be hard-pressed to get the lens as sharp as the Sigma. It is spectacular.