I have pre-ordered this lens, expected to be released approximately January 17th, 2014. I am surprised there's been no mention of it so far in this forum. I will be happy to put up a review and samples as soon as I get my hands on it. I will be replacing my venerable Tamron 200-500mm lens, which has served me well for 5 years - the new lens will add 50mm on the wide end, 100mm on the long end, USD motor instead of screw drive, focus limiter switch and AF/MF switch, new coatings, and moisture resistant construction. The early reviews have been very positive, and the samples and tests seem to bear out a pretty sharp lens even wide open at 600mm, and quite good stopped down a bit. The release price in the U.S. is a very reasonable $1,069 - hard to imagine autofocused 600mm F6.3 for that price! Mine's in Sony/Minolta mount, so no VC since it's in the camera body - Canon and Nikon versions will also have VC (stabilization). Hopefully the lens will be released on the scheduled date and not be pushed back - we'll see!
Sony DSLR-A68 / Sony 18-250mm / Minolta 50mm F1.7 / Tamron 150-600mm / Minolta 300mm F4 APO
Sony A6300 / 18-55mm F3.5-5.6 / 55-210mm F4-6.3 / 10-18mm F4 / 35mm F1.8 / 16mm F2.8 / FE70-200mm F4 G OSS / FE70-300mm F4.5-5.6 G OSS / via manual adapter, lots of Pentax K mount, Konica K/AR mount, and Leica M mount manual lenses