AR is a funny word. As most often used, it refers to a visual mechanic, whereby real feeds and virtual or informational feeds are layered. AR view in ARIS (via vuphoria) and ARKit focus on this, but in different ways. Vuforia is based around image recognition though not always flat geometry, and using media to integrate, while ARKit is based on spatial geometry and animation that uses those scaffolds from the real world. There are more general definitions of AR (Pokemon Go mostly works using GPS for example), which ARIS also incorporates.
So there is some difference in the media environments created, but maybe more importantly, who can make use of them. ARIS is for everyone. My student used the available tutorials and forum posts to figure out ARview on his own with no technical background. ARKit is for iOS developers.