Hi there,
I also have this lens, with a Nikon 1.7x TC. All my pics on this thread have been shot with this combo.
http://forum.scramble.nl/viewtopic.php? ... &start=150
I use it without TC for helicopters, large planes and WW2 stuff, it gives real stunning results. I also get great shot with the TC, but the light really improves the hit ratio, and a bit sharpening and contrasting is needed in post processing (I use Lightroom). But still much much better than the sigma.
Another great thing about this lens is that it is so much lighter than the bigma. I used the Sigma 70-200, 100-300, 50-500 and boy am I sorry for not having bought this lens earlier. And at least I know I will not be upgrading soon, as the next step is so much more expensive
Finally do not think about the drawbacks of a prima. You WILL have enough oportunities to take pics, only from another angle. The only difference is that you will have a HELL of a job sorting your keepers once home...
Believe me, sell a kidney and buy the lens now, if you don't you will realize next year that you threw one more season away!
Greets,
Arthur