Canon 6D vs Nikon D600 ?
I don't think anyone can make a broad statement. Ken loves vivid jpegs, and Canon seems to do a better job with jpegs noise versus RAW photos. So a lot depends on how you use the camera, ergos and your lens requirements. If you value shooting movies in crop mode Nikon can do that. Can you live with the slower fps, maybe yes if you do portraits, but not for sports. A lot depends on what trades off are important to you and what you already have in your photo system.