There is no reason to upgrade to a new camera model because the mark IV is an improvement over the mark III (now both cameras), the 6D is an improvement over the Nikon D3s and the Nikon D700 is an improvement over the Nikon D200, and so on and so forth.
Discontinued Canon EOS 7D Digital SLR π· Camera Body Only with 18 MP CMOS Sensor
88 Review
Nikon COOLPIX L810 Digital Camera: 16.1MP, 26x Zoom, NIKKOR ED Glass Lens, 3-inch LCD (Blue)
95 Review
Canon PowerShot A480 camera, black
108 Review
Nikon D3100 DSLR Camera Body (Kit Box) - No Lens Included, International Version with No Warranty
298 Review