This will supplement my Sigma 100-300 f4 perfectly since I don't have a 70-200 2.8. In all honesty, in most situations where the 70-200 would be nice, what I probably really want is a 135 f2 anyway. I bought it mostly so I can do some nice portraiture stuff and swimming, diving, basketball, indoor tennis, and... well that's all I can think of. Yes, I bought it new from B&H, because I buy all my glass new because I like to be able to return it if there's anything wrong with it. Also, I got my gadget infinity remote triggers and my cheapo lighting kit (two stands, two 32" umbrellas, two clamps) to go with my B1600 and 580EX. I spent last night raping my downstairs roommate with high-power flashes shooting at ISO 100 F32 just for the hell of it. Unfortunately, I have the sigma 1.4 converter which I have heard causes some AF anomalies with this lens. We'll see how they work together.