Feedback AR Foundation vs Vuforia

I’m looking to gather information about AR Foundation vs Vuforia. I have clients who are interested in AR Applications, and I’d like to figure out which platform would be best for me to recommend developing on. Right off the bat, Vuforia, especially for Enterprise companies, comes with a hefty price tag, whereas AR Foundation is open source. Here are some specific questions I’m looking to get answered:

Backwards Compatibility:

• How far back for iPhone and Android does each platform go? Basically what’s the oldest phone that is able to run an app using either platform?

Image tracking:

• How stable is the image tracking? This is something Vuforia is known for, but I’m curious as to how AR Foundation stacks up?

Plane Based tracking:

• How stable is Plane based tracking? In this same vein, what about Area tracking, or model/object tracking?

Examples and Case Studies:

• Any use cases of AR Apps utilizing either platform. Specifically Fortune 500 companies.

 

I have some of the same questions, and found this interesting on the topic, for anyone else who is looking:
https://www.reddit.com/r/Unity3D/comments/ldcl6v/ar_foundation_vs_vuforia/