From what I can tell Nikon makes better DSLR's, and Canon has greater market share, probably due in large part to their historical market inertia and excellent lenses. In many markets Nikon has overtaken Canon, and they seem to be investing the R&D dollars that Canon is not.
A few years ago when I was shopping for my first DSLR it was clear that the Nikon was the better camera in the market segment I was searching, and Canon did not make the lens I wanted, and their flash system was way behind current technology. I had expected to buy a Canon, but they just weren't there in so many ways. So I had to buy a Nikon. An engineering decision, not an emotional one. I don't shop by product popularity, but by image quality, user interface and product features.
I think we are better off if they compete rather than merge. Can you imagine the fight over lens mounts if they did?
Enjoy your Canon, Mike!