Hi Juan,
All the latest versions of the browsers are pretty good for the best-known HTML5 features, even IE 9. And you can always check up on a browser by pointing it to
http://www.html5test.com. However I wouldn't say there's a best one since you need to cater for all your users, and should therefore treat them all equally.
The following website lists all the HTML tags, including HTML5:
http://www.quackit.com/html_5/tags/. Click on each and you can interactively experiment with the tag.