I've been considering this lens for a while. I got the chance to handle one at PMA a couple of weeks ago. Based on this and some discussion with other sports shooters I'm going to get one. While looking at pricing I've discovered a 25% price difference between grey mkt and USA versions. Sigma4less sells the grey mkt lens for $2159. The USA version at B&H costs $2699. While I've bought and sold used camera equipment since the late 70's this is the most I've ever spent for one item. I'm not worried about focus problems as I would expect to find this immediately and sent it back to the retailer for another copy. I'm more concerned about oil on the aperture blades or HSM problems after the 1 year warranty expires on the grey mkt lens. A 3 year Mack Warranty cost $60, but has lots of exclusions. I guess my question is: Is the USA version with its 4 year warranty worth an extra $500?