Also, the lens allows full time direct MF. That means you can manually focus at any time regardless of which mode it is in. If you are in one of the AF modes, it will AF again the next time you depress the shutter half way.
I have been used to this in the Nikon gear I use, and I actually hate it - if your hand slips and hits the focus ring after the AF finds, then it adjusts focus through DMF. Having full time DMF engaged I've found to be way more problematic than helpful, and its only worsened by the fact that the zooms on the end and the focus on the front of the lens. However, its certainly a small price to pay to have such terrific optics and SSM.

I've been wanting to get this particular one, for its range/quality/price, but my main advantage I want it to have over the can is AF speed. Canuck - I ssume it should find focus quicker than an f/2.8 screw driven AF motor, please let us know what you think of the AF speed, and IF it does compare as such.