AND here's the "other" side of the Canon vs Nikon debate...look here, and watch as the Canon at its BASE ISO level performs as only an outdated sensor can...Canon is realllly sucking hard in this example....
Part II - Controlled tests
I'm not impressed by ANY image shot at ISO 25,600 or over 50,000 ISO...no matter what the camera, those images offer execrable quality. But, the Canon fanboys loooove to talk about miniscule advantages they think they see at sky high-ISO values.
The thing is--Canon is ONLY even remotely close to Nikon in the 1DX and the 5D Mark III and the 6D...the remainder of the Canon line is seriously behind the times, technologically speaking, and is basically built around
the same 18-MP sensor that Canon debuted in the 7D back in 2009...no real, appreciable improvement since 2009 for Canon users, UNLESS they buy one of the three Canon full-frame models...
Nikon is using MUCH newer sensors made by SONY, and by Toshiba in its APS-C cameras. Pentax is using the same SONY-madse sensors as Nikon. SONY is using their own sensors. In both FF and APS-C, Sony and Nikon, and in APS-C, Pentax also, have the best-performing sensors. Sorry Canon, but it's true. The lead Canon once had has been lost, due to FAILURE to update its outdated .50 micron sensor fab machinery to the newer, better .18 micron fabrication process that Sony and Toshiba have invested in.
For the user who is going to buy a brand-new APS-C d-slr, the advantages Nikon offers in image quality are, I think pretty compelling. In FF d-slr, I think Canon makes a compelling value proposition with the 6D.
Canon on the other hand, sells more cameras. Just as Toyota sells more cars than BMW. But sales numbers do not mean that the product is "better" in any way...only more popular, or more widely-sold, or whatever.