These are statistic charts of each of the three tablet comparisons to screen display.
Amazon Fire HDX 8.9
Tablet Price: $379.00
Screen size: 8.9 inches
Display resolution: 2560 x 1600
ppi (pixels per inch): 339
Type: Fire OS 4
Apple iPad Air 2
Tablet Price: $439.00
Screen size: 9.7 inches
Display resolution: 2048 x 1536
ppi (pixels per inch): 326
Type: Apple iOS 8
Samsung Galaxy Tab S 8.4
Tablet Price: $397.99
Screen size: 8.4 inches
Display resolution: 2560 x 1600
ppi (pixels per inch): 359
Type: Android 4.4 (KitKat)