Any of you guys have this lens? I was debating whether to get this lens for my D700 or just save up the money and get the 28-70 or 24-70 Nikon versions. Is it a hell of a difference or would this hold me over for some time. I realize glass matters more than the body and I don't wanna spend my money on something I'll regret buying a few months down the road. What are your experiences with it?