i have found both these lens for sale locally and think either one would be a great addition to the little gear i have. i have read reviews on both and surprisingly alot of people have said the sigma isnt that sharp even with a f2.8 all the way across the board...alot of reviews have said despite a f3.4-4.5 the nikon is pretty sharp for what it is. im honestly worried about pincushion distortion at 85mm on the nikon/70mm on the sigma. i still plan on using my lil 50mm in most situtions(cause i just love it) but i need something a little longer...who has personal experiences with either one of these lens? there are alot of people on here that are alot more experienced than me when it comes to this stuff and i just need some input from others.