Whew. I don't think your question can be answered as posed.

I mean...best for what interests and age groups? Private or public? Best for what kind of kid? A kid who likes to go into lots of depth on stuff, or a kid who wants to take in as much as possible as fast as possible, or someone in between? A child with one very keen interest? Or multiple interests? A kid who might resist a lot of homework? A kid who will conform and do whatever is asked?