Nice article James! Surely helpful for those wanting to change systems, for whatever reason.
The later question of which camera is better than the other has been going on for years, and will go on for many years to come. It's almost a religion
Right now, I think Canon and Nikon are just so incredibly similar, it's almost useless to even try and compare them. Sure, there are minors pros and cons, but they truly are minor. They are both great systems, with wonderful lenses, and whichever you choose, you will be happy with it. If you already own a whole bunch of lenses, for most people it's just the best to stay with that system imho. And if you think the 'other' system is better this month, just wait and use your trusty current system a bit longer.
Concerning upgrading, I force myself to use a camera for at least 2 to 3 years. After that period, I see if I feel i could speed up my learning curve with a more modern system. It's easy to say you'll get better results with a better camera, but for most people that's probably not true. Im still quite happy with my D100, for what I want and need to do with it. And if I want anything 'better' (good/better/best are so subjective), I'll grab my Nikonos or my wife's F100 
I own and sometimes still use a 25+ year old camera (Olympus OM1). Even after so long, it still produces great images (astronomy mostly). Why we even let ourselves buy new (expensive) digital cameras that often... the holy grail of pixels,
cor