In this video US photographer Tony Northrup does a great job of telling why he wants to switch from Canon to Nikon but can't.
In a simple row of very sober arguments and conclusions about the availability and specifications of his key lenses, he simply demotes Nikon as not being able to deliver what he needs in spite of having a body he really wants, the D810.
In the flurry of Nikon-is-better-than-Canon, Nikon-is-loosing-it and Canon-is-lagging-behind hysteria, it is liberating to get an objective analysis based on facts.
Well done Northrup!
PS: I still prefer Nikon