Upload & Sell: On
I'm almost ready to pre-order the thing. Most of my field sports work is done on my 70-200 IS II with 1.4xTC and the Tamron weighs a few ounces more but offers twice the reach. With my 1DX I can easily adjust ISO for the f6.3 and put more pixels on target. So far the examples seem to show that it's a good match with a 100-400 and an older 300/2.8 with TC. That's pretty high quality for $1000 IMO.
Yep. I'd much rather cart this thing onto a plane, than the 300/2.8L IS or 500/4L IS. I expect it'll have compromises in at least a few performance areas, but that could be quite alright, depending on the details.
Anyway, I'll wait to decide until after production lenses have been acquired and evaluated by trusted FM members. So far, it looks pretty darned good. OTOH, that was my original take on the Sony A7R, and now I've decided to wait for an A7R release with EFCS, or a new, high pixie EOS body from Canon. I've done enough early-adoption in the past three years; I can wait a bit this time.