It's not. AWS goes out of their way to make mixing it with other providers so expensive that no-one will do it unless they absolutely have to, because they are

It's not. AWS goes out of their way to make mixing it with other providers so expensive that no-one will do it unless they absolutely have to, because they are chasing lock-in. CloudFlare basically does the opposite—their whole thing is positioning themselves as an intermediary so they can snoop on and get a cut of the action on everyone "else's" traffic... and then cut everyone else out completely, as they bring more services to market. They are positioned like a boa constrictor, coiling around all their partners and providers that sit behind them. They are not mainly a CDN and aren't even particularly interested in competing with other companies that are mainly CDNs, which becomes crystal clear if you ever negotiate enterprise pricing with them. The CDN's just a means to an end. Nb. despite all that their public-pricing plans are such excellent values (though, beware, last I checked the $200/m one was the only one with any kind of SLA whatsoever, and not an impressive one) that if I were creating a start-up CloudFlare might well be the very first service I signed up for. If you're a small fish it's damn hard to justify not using them. And the coils squeeze a bit tighter....