The Nikon D610 brings full-frame capabilities to a larger audience while retaining most enthusiast-friendly features. Image quality at high ISO sensitivities is very good, and a wealth of customization options enables quick access to most shooting controls.
The Canon EOS-1D X is a camera meant for advanced photographers. It's physically imposing, with a big design. It incorporates portrait and landscape shooting controls.
The Canon T6s takes the Rebel series up a notch. With its 24.2 megapixels sensor, the Canon T6s shoots excellent images with tons of detail and accurate colors.