Good Bye w3schools.com ?
I prefer it when I need a quick refresher on an HTML element because it's especially good for having short, simple examples I can copy and paste.
MDN tends to be verbose and technical. It's good when you need to know everything in detail, but often I need a quick refresher and a simple example and for that w3schools.com always seems to have better content.
Compare these two pages for input types:
https://www.w3schools.com/html/html_form_input_types.asp
https://developer.mozilla.org/en-US/docs/Web/HTML/Element/in...
The MDN page is more complete, but reading it gives me a headache.