9 out of 10 points and recommendedWell made both optically and mechanicallySome concern about front focus issues.
I have had this lens for only a week but have done several tests on it. The sharpness is excellent at 50mm and 100mm, and very good at 150mm. The corner sharpness is better than my previous lens which is the Nikon 70-210 F4. Center sharpness is a little worse. This is comparing the Nikon at F4 to the Sigma at F2.8. I find the colors to be excellent, best I have seen, much better than 18-70 kit lens for D70. I measured the focus speed again the Nikon 70-210 F4 and the 18-70 3.5-4.5 Kit lens. Ends up closer to the 18-70mm lens, but the difference between the HSM, AFS and older screw drive was much less when actually measured than what I thought just by listening to them. Overall, a well balanced winner. I love the 50-150 length as well, much more natural than the 70-200 given a digital camera's 1.5 crop factor. Posted some pictures here:reviewed December 2nd, 2006 (purchased for $639)
UPDATE: 1/18/07 - I just found out that this lens and my other HSM/AF-S lens do not like cold weather. I left both outside in my car for about 5 hours at 30F (freezing). My 50-150 would not focus, nor would my 18-70mm Nikon AF-S lens. My screw drive 50mm would. Consider this before purchasing. I still love the lens by the way. Love the 50-150 focal length better than 70-200.