<p>At a purely technical level, there's not a lot of difference between Nikon and Canon, and certainly none visible to the naked eye. There's difference within the manufacturer's range of products in both cases - a Canon 1DX is not designed for the same uses as the 6D, and both are far more capable than a 1200D.</p>
<p>Worrying about DxO ratings and counting pixels is silly. The camera of whatever make, shape, size or type is a device with but one purpose - to record, more or less, the image in front of it. That raw digital file is the modern equivalent of the negative. It is a starting point only. You need to process the file just as you need to adjust the image from the negative in the darkroom. Expecting a "perfect" digital file is like wanting a film camera that will always and only produce the perfect negative that can be printed without dodging and burning, without filtering, just straight to paper. Such things don't exist.</p>
<p>Keep your Canon stuff. There's nothing wrong with it (disclaimer - I use Canon, for no better reason than that I always have). If the Canon is 0.001% inferior or superior to the Nikon in ways that the human eye cannot discern, what does it matter?</p>