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.
Andy Rouse is very famous for being exceptionally outspoken about the Canon 1D MkIII AF issues, until then he was a solid Canon shooter, he very publicly trashed the camera, and Canon, and moved to Nikon. He has since grown up a bit. He didn't get on with the Nikon D4 very well and when he compared the Nikon's he was using to some loaner 1DX's and the MkII Super Tele's he ate a bit of crow, said he was above such petty behavior as comparing manufacturers, dumped all his Nikon gear and now shoots exclusively Canon.
He has said, leading up to this, for his work the MkII tele's and the 1DX are the best available, he has also said he buys his own cameras.
Does that imply that he does not buy his lenses?
5D IV, 5DS R, 7D II, EOS-M, Powershot G3 X, 400mm DO II, 300/2.8 II, 1.4xTC III, 2xTC III, EF 1.8 STM, EF 70-200/4 IS, EF 24-105, 15-85, 100-400 II, Sigma 10-20, Sigma 150-600mm C, EOS-M5 15-45, f/2 22, 11-22, Samyang 8mm f/2.8 fisheye