2n10 wrote in post #16717742
Canon doesn't have the DR of Nikon so you will need to learn to expose to the right (ETTR). The 5DIII should be better at ISO 3200-6400. It also does even better the higher the ISO you go than the D700.
This. The 5D3 is a great camera, but you will also need to learn how to use it. Coming from Nikon, you will have a learning curve and several frustrations with using buttons, dials and menus.
Snapsort is not a very good indicator of a better camera. Their algorithms are highly biased towards price and Nikons are always less expensive and therefore always get the higher rating. Look at real-world, practical reviews.
This. Although the D600 was plagued with problems from the beginning, Nikon fixed most of the issues with the release of the D610. I've heard great things from friends who have one. Although if you're looking at a 5D3, the Canon will have the better AF system.
Hogloff wrote in post #16718799
Really depends on what other Nikon gear you have. If you are fully equipped with Nikon, I would not jump ship. If you only have 1 Nikon lens, then I might consider it.
This. Both Nikon and Canon are great systems. Buy the camera body that you have lenses for. It's not worth switching everything over if you're highly invested in one system, unless you absolutely need a feature of the other. MOST of the folks that shoot Canon, started with Canon. Those that switched from Nikon, either switched when everything went digital or were at a point where their gear was minimal and the investment to switch was reasonable. Obviously there are the few that spent a small fortune, ditched everything and switched over, but those are more the exception.
Also remember, this is a Canon forum. There are a few Nikon folks lurking about, but that's because Nikon doesn't have this type of community. 
Good luck.