I guess it was easier with film. All I remember being concerned about was optic quality of lenses, shutter speeds and durability of the camera. Both Nikon and Canon were very good at everything, mechanically. It wasn't until technology started to ramp up and AF was introduced that the differences between Nikon and Canon really began to show. Canon redesigned their mount and came out with EF lenses with built-in motors and Nikon decided to keep their traditional mount dating back to 1959 and initially kept the motor inside the body. The AF and metering systems became more advanced and each had their strengths and weaknesses.
Image quality was much more a function of what film you used and how you processed the negatives. Of course, when shooting slides, the window of processing became much narrower than with negaitves. I remember choosing Fuji Sensia or Provia for bright colors, Kodak Portra 160/400 for portraits, weddings and natural skin tones and Kodak T-400 for B&W. I remember pushing B&W film to 800 or 1600 sometimes to get that grainy look.
It seems that with digital, all those choices of film now come rolled up into what camera you get, versus how you process the image in PP. That, coupled with nifty gadgets and doo-dads like touch screens, wi-fi, built-in flashes, HDMI output, etc seem to set the two apart.
I own a 5D3 and a 30D and still use them the way I used to use my grandfather's Nikkormat FTn. I meter, I focus and I take the picture. For those purposes, either brand will serve my needs. I prefer Canon simply becuase I find it easier to meter, focus and take the picture. Not because it has this feature or that feature. I may be old school, but I venture to say that I'm not the only one who thinks this way.
The younger generations that grew up with Nintendos, Playstations and Xboxes may be swayed by all the gizmos and gadgets offered by one brand of the other, but the generations of Atari 2600s and older still use a camera to immortalize a special moment with a photograph, not upload a snapshot of your sushi roll dinner to Facebook.
I'm not trying to belittle the technologies offered by each brand. I'm just trying to point out that each camera is fundamentally, a camera. Both of them meter, both of them focus and both of them can capture a good image. Everything else is just window dressing for me.