I have read all the old thread regarding both lenses but was wondering if anyone had actually bought the sigma in the mean time and had some thoughts on it. I am also considering getting in line for the 18-200 VRII and getting a teleconverter but I think I really want the range of the 400. So pretend I am not even considering the 18-200 but have my heart set on the big boys do you all have any advice. EDIT: I am young and dumb so I am not too concerned with the sigmas heaver weight. This is the part where I blame my wife for allowing me to contract LLD. I casually mentioned that it was about time I get some real glass. And instead of freaking out she just wanted to know if it would enable me to take my photography further. WOW!! I don't have any $$ but that shouldn't stop one from dreaming right?