The site derives its name from the abbreviation for the World Wide Web; W3 is a numeronym of WWW. W3Schools is not affiliated with the W3C.
It is created and owned by Refsnes Data, a Norwegian family-owned software development and consulting company.
Most of the tutorials here are for free and are mostly recommended by experts who are also proponents of the subjects mentioned above.
I can’t say it’s best or not unless you give it a try yourself.