I hate being cynical, but he has had the lens for 6 months and no doubt would like Canon's next toy for 6 months or so too. That does not tend to happen when one is too critical, or sometimes even negative towards the toys they offer.
Still, an interesting read, and I look forward to reading more from others.
I agree, I believe Andy may have been a little disingenuous, I have a few friends that are Professional Wildlife Photographers, they happen to all work with Nikon unfortunately, and they all Buy their own gear, there are probably very few Pros that Canon or Nikon supply free gear to, but two of these Pros are "loaned" equipment to try out & as long as they write up positive reviews, in this case for Nikon, the equipment loans are viewed as "long term".
I was in Africa in March shooting with one of these Pros, he currently uses a Nikon a pair of D3x Bodies and in particular the Nikon 200-400f/4, when I left to come home I lent him a 1Dx & the 300f/2.8 v2 & 400f/2.8 v2 Lens to try as he was considering flipping to Canon (because of the 1Dx), his views over the last couple of months of comparing were interesting, at 400 there is simply nothing to compare, the 1Dx + 400f/2.8 v2 combo "Murders" (his word) the Nikon D3x/200-400f/4 combo @ 400 (but to be honest the Nikon 200-400 has always been soft at 400), his view on the combo at 300, was the same if not more so, the 1Dx/300f/2.8 v2, "murders" the Nikon 200-400 @ 300.
But, and this is the kicker, his view was the straight up "flexibility" of the Zoom in fast action wildlife, still gave the Nikon 200-400 the edge in his opinion, as long as your Technique was excellent, he was prepared to give up better IQ for flexibility. Of course it's all debatable, and this chap is a long term Nikon shooter, but it was interesting view non the less.
My feel at the moment is that the Big White Primes are still going to have the IQ edge over the New Canon 200-400f/4 1.4x, at 200/300/400 & definitely at 600 (compared to 560 with a 1.4x), but i have little doubt the IQ of the Canon 200-400 will trump the much older Nikon 200-400, and that Nikon 200-400 isn't a bad Lens, the flexibility is what will be a decider for myself, the flexibility of the Zoom at these distances (200-560) will be just awesome & if the IQ is as good as I expect, and as good as Andy Rouse's Images show, it'll be a definite Lens in my Bag.
Now, I need to head out & sell the wife's Car before she comes Home, and then off to the Gym to build up those arm muscles.