We are not able to recognize any major difference in the image quality of between Nikon D5500 and Nikon D7200, however at ISO 6400 Nikon D7200 grabbing bit more details compared to Nikon D5500, so if you don’t need advance AF system.. don’t put your extra money on the Nikon D7200 camera.
Buy Nikon D7200 from Amazon || Buy Nikon D5500 from Amazon
Also See Nikon D7200 High ISO Test