I demoed it a while ago, maybe I'll take another look. My real point was that you don't need to install any unfamiliar software. I love Varnish, but if the default VCL file doesn't work for you, there's a learning curve.
CloudFront... Fastly... CloudFlare... I'd agree that many projects should just adopt a cache-as-a-service, rather than add another layer/process that must be learned and maintained to their own systems.
Sure. Any CDN is better than no CDN. :)
$50 monthly minimum at fastly means it's not a great plug-and-play replacement for smallish sites.