"Hey Siri" support and possibly wireless charging case alongside AirPower charging mat.
DisplayMate iPad Shoot-out: iPad Mini 4 Has Best Display, But iPad Pro and iPad Air 2 Also Perform Well
DisplayMate called the iPad mini "unquestionably the best and most accurate LCD tablet display we've ever tested," giving it higher marks than the 2732 x 2048 resolution iPad Pro. The iPad Pro also scored well, earning all "very good" to "excellent" marks on tests, and while the iPad Air 2 did well enough to rank as a top tier display, its performance was somewhat behind the iPad mini 4 and the iPad Pro, unsurprising as it was last updated in the fall of 2014 while the mini and the Pro were both released in the fall of 2015.
All three tablets use the same IPS LCDs, but the iPad Air 2 and the iPad Pro have photo aligned LCDs with higher contrast ratios while the iPad mini 4 uses standard mechanical alignment. The iPad Pro also uses a metal oxide TFT backplane for better light throughput and power efficiency, a must for such a large and power hungry display.
Each of the iPads has a similar max brightness, measuring in at 415 cd/m2 (nits) for the iPad Air 2, 424 nits for the iPad Pro, and 450 nits for the iPad mini 4. On maximum contrast ratio, the difference between peak white brightness and the darkest black, all of the iPads had high True Contrast Ratios, but the iPad Pro won at this test. The iPad mini 4 had a True Contrast Ratio of 967, while the iPad Air 2 ranked at 1,064 and the iPad Pro measured in at 1,631, the highest DisplayMate has measured for an LCD tablet display.
On color gamut, the iPad mini had the most accurate score at 101 percent (100 percent is best). The iPad Air 2 had a 105 percent color gamut, while the iPad Pro had a 107 percent color gamut, with the larger two tablets displaying oversaturated blues. On color accuracy, the iPad mini also won, but the iPad Pro was a relatively close second. The iPad Air 2 earned much lower Absolute Color Accuracy marks.
The iPad mini 4 has a very impressive Absolute Color Accuracy with Average/Maximum Color Errors of 1.9 and 4.2 JNCD - tied for first place in Absolute Color Accuracy with the Microsoft Surface Pro 4. The iPad Pro is somewhat less accurate, but still (just barely) Very Good, with Average/Maximum Color Errors of 2.6 and 6.6 JNCD. The iPad Air 2 has noticeably lower Absolute Color Accuracy with Average/Maximum Color Errors of 3.9 and 8.8 JNCD, which are visually noticeable and could be unacceptable for some color critical applications (like medical imaging, high-end digital photography, product sales demonstrations, and advertising proofs, for example).When it comes to screen reflectance, DisplayMate called all three iPads "unrivaled record holders" for performance in ambient light. The iPad mini had a 2.0 percent Reflectance, while the iPad Air 2 had 2.5 percent and the iPad Pro had 2.6 percent. A test measuring contrast in high ambient light saw the iPad mini perform best, with a Contrast Rating for High Ambient Light of 225. Comparatively, the iPad Air 2 scored 166 and the iPad Pro scored 163.
Due to the inclusion of the metal oxide backplane in the iPad Pro, it earned the award for most power efficient. The backplane increases light throughput and the iPad Pro's display uses a lower refresh rate when there are static images on the screen.
While the iPad mini 4 is the best iPad display based on DisplayMate's test, the site calls all of the iPads in Apple's current lineup "unrivaled" when it comes to screen Reflectance, giving them an edge over competing tablets. Due to their low Reflectance, the iPads have "by far" the highest image Contrast in ambient light and the highest Contrast Rating for High Ambient Light of all current tablets.
The full results of the display shoot-out, available from DisplayMate, are well worth checking out for those interested in getting an in-depth look at how the displays of the iPad mini 4, iPad Pro, and iPad Air 2 compare.