Though Google ARCore has fewer results in github repository as compared to ARKit, it still has a more stable platform and better documentation to make the development process easy. One can do experiments very quick and easy with ARCore to try out various features. Amazon …
Apple ARKit is best where AR experience will enhance user understanding of the product. For instance, for a furniture app, AR via Apple ARKit can help users get an understanding of how the furniture will look. It also works well for use cases where we want to give human movement as an input for AR, so for instance for clothing apps that want users to see how they will look in a particular clothing style, etc.
ARCore is well suited for demonstrating 3D objects on surfaces that could be used mostly in product sales, real estate. It can be used to measure objects or a room to make a 3D architectural model out of it, although it's not 100% accurate it can give a pretty good idea. It can be used for games and marketing reasons ARCore is less appropriate for human body tracking, occlusion, and large-scale augmentation where there needs to be a large-scale scanning.
Vuforia Engine has limited functionalities compared to ARCore. It has image-based detection and augmentation which requires users to have the anchor image with them for the augmentation to properly occur. ARCore solves that and it's one step less to reach the user and really convince them to try it.