Re:Apple’s AR is closer to reality than Google’s
by cptn_brittish on Monday June 26, 2017 @11:57PM
(#14642478)
Some of the higher comments go into this and it appears that ARKit only implements some of a full AR Stack (Visual Inertial Odometry) while Tango supports it all (SLAM) so it can also have persistence between device reboots and be useful in bigger applications.
I will note I am just repeating the comment and you can see it here: https://news.ycombinator.com/item?id=14640682