Has anyone seen a review or know someone that has this lens yet? I see that a store in Canada has them listing for $629 CAN!!! That's $170 cheaper than the Nikon equivalent. I'm not crazy about f/6.3 but I'm wondering whereabouts it turns to that. I have a 70-300VR that I don't mind mounting so if it's too slow, the 70-300VR will see action. http://www.thecamerastore.com/ProductDetails.aspx?productID=32488 Anyone? Very tempting!!