So I played a little this morning w/ the Russian Beast, tamzooka and the Canon 70-200 II.

All results are at f10 or f11 The results.

Russian lens is slightly better in resolution than 2x Tamzooka - contrast slightly and I mean slightly less in the Russian.
Tamzooka at 650 is better than Tamzooka at 400 scaled to 650
Tamzooka at 200 and Canon at 200 are pretty much equal (DUH its f10!)

Is it worth dropping $300 on a beast..... Nope - I couldn't really justify it by the IQ step up. I suspect the Sigma at 2x would beat the Russian (Sigma is definitely sharper than the tammy at 650) AND you wouldn't have to carry an extra 10 lb non stabilized beast, etc, etc. Have to spend another $500-600 on the set up but trade offs are likely worth it if you really have to go that extra 1/2 mile. Brant can opine on the Sigma w/ teleconverter and w/o 2x IQ

The target image was at 300 meters (laughable at any level) - which is just short of infinity for the Tammy and an a little longer throw for the Russian. From what I can tell, the closer to infinity the better for the Russian. So maybe there are a few more pixels to resolve at infinity.

Yea, I am not going to post them - you are going to have to trust me - or you can buy my Russian for $300 .

Mike