I've been a Nikon user for 10 years and have long noticed a degree of enmity and competition between Canon and Nikon users. Canon users seem almost messianic in their conviction that all is roses in Canon-land.
I currently use a Nikon D70, having used, and in some cases destroyed, numerous bodies including an Fe and an F90x. But I remain frustrated by Nikon's line up. They have no wide angle tilt shift lens, no series of pro-grade but modest aperture zooms (e.g. Canon 70-200 F4 L), no AF 400mm F5.6 lens and so on. And of course though the D70 and D2x are first rate, there is still no D100 replacement and no FF DSLR. Nikon are undoubtedly lagging Canon in the DSLR war, although the D2x is by all accounts superb. (Some people are migrating to Nikon specifically to use the D2x.) For years I was driven mad by the lack of AF coupled extension tubes, and the third party ones I bought were of poor quality and fell to bits.
Oh yes, and in the UK Canon lenses are often much cheaper than Nikon ones. Ouch.
On the plus side, Nikon do produce nice bodies, that last yonks, and nice lenses. There's a huge pool of used manual lenses that are cheap as chips and yet are the bee's kness (or the badger's nadgers if you prefer). Their primes including the wides are generally excellent, and many zooms are first rate. So there's a lot that's good with Nikon.
So, to some questions:
Why do Nikon have so many missing gaps in their lens line up? Or do Nikon users never want to use a wide tilt shift lens? And why no AF extension tubes that work with all AF lenses? The only answer I have is lack of development capital or a really perverse marketing/business strategy.
What weaknesses do Canon have? I have heard that Canon wide primes are so-so and some criticise the flash system.
BTW I hope this does not start a silly "my camera is better than your camera" war. No system is perfect.
Leif