20 years ago when batteries powered meters but not shutters, there was a real difference betrween Nikon and Canon - the Nikon F2 was the journalists' camera, but Canon made better telephotos so sports and wildlife guys used Canon.
Then when autofocus came in, Nikon made their old lenses compatible while Canon changed the lens mount and old lenses were useless.
None of that applies today - both are cutting edge companies - buy which feels good.

One thing does remain - if I do without autofocus and autoexposure, my 20-yr old lenses still work on a new Nikon.