In my opinion this is comparing apples to oranges.
CloudFlare emphasizes the security side (anti-DDoS, WAF) while CloudFront goes for the pure CDN side of things. I would compare CloudFlare to e.g. InCapsula and CloudFront to Rackspace Cloud Files / Akamai.
CloudFlare emphasizes the security side (anti-DDoS, WAF) while CloudFront goes for the pure CDN side of things. I would compare CloudFlare to e.g. InCapsula and CloudFront to Rackspace Cloud Files / Akamai.