Btw comparing a 5D3 with the D810's latest features is not really fair, because the 5D3 is a 3 yrs old camera, and technology is rapidly progressing. If you always want the latest camera technology, you'd have to change systems about every six months...
There have been several comments to that effect in this thread, and I totally disagree. It's perfectly fair to compare Nikon's current
high-end FF body to Canon's current
high-end FF body.
The 'unfairness' is the biased comparison in the linked video. Comparing only at ISO 100, that smells like DxO's BS (but then, lots of people – including some pros – seem to like that smell). Someone asked about performance at ISO 12800, he said he'd post samples but that the D810 was better...yet he didn't post samples. No follow through, or he couldn't back up his statement with images? A 63% hit rate with 5DIII Servo tracking of a subject walking slowly toward you in bright light (even his wife knew that wasn't a 'sports/action' test!)? Maybe...if you gimp the test by using an AF mode not recommended for moving subjects. Even then, that seems too low...but maybe that's due to the lens, as I've read that Nikon makes their AF algorithms available to 3rd party lens makers while Canon does not.
So, while it's fair to compare them, performing a biased comparison doesn't help anyone. Well, that's not true – it helps him earn money...and a reputation worthy of Ken Rockwell.
The reviewers takeaways on the 5DIII vs D810...the D810 is vastly superior, but: "If you have a Mark III and you're not a pro, it's probably not worth switching,
" and, "If you're putting photos on Facebook...it probably won't make much difference.