I enjoyed the review, thanks! I've got this lens on order and am pretty excited to use it.
A direct comparison is really hard to do, given so many variables. It can't really even be compared straight across to the primes, in that they're used so differently. Having said that though, the mention of it replacing several focal lengths and the associated cost savings neglects the fact too, that in order to have the use of more than one focal length you would also need to own (and carry!) at least one other body. To go from switching bodies to twisting the zoom, at these focal lengths...such luxury. With the price to match, unfortunately.
But I think it will be absolutely perfect for my main uses: air shows, outdoor sports, and large wildlife. And I can't wait for the horse racing season here in Dubai!