Vuforia vs ARFoundation for markerless tracking

So in addition to user and predefined image targets Vuforia also acts as a wrapper on ARkit and ARCore, and implements their own Ground Plane technology for markerless tracking on non-iOS or Android devices.

So my question is, why wouldn’t you ALWAYS use Vuforia over ARFoundation since it seems to offer more functionality and cross platform compatibility?
Is their ground Plane technology inferior in some way to that in ARFoundation?
Any useful comparison demos out there?

I have a client that swears by ARfoundation. Says that ARF drift/stickieness is far better than vuforia.

I made him 6 AR apps with every AR unity plugin imaginable, and thats the feedback I’ve gotten.

I don’t notice a difference because I dont actually use the apps I make apart from testing (lol)

Thanks for the feedback! Hoping that someone might publish or share some tests comparing the 2 as well.