What are you favorite CDN?

Best CDN is no CDN. Keep your list of dependencies small. Serve them yourself. Wikipedia just did a great job on this, see https://phabricator.wikimedia.org/phame/live/7/post/175/wiki... and corresponding https://news.ycombinator.com/item?id=21016972

Bonus: You don't get CDN trouble, like having all your visitors tracked.