The free version of Cloudflare CDN is a good start. But if you have lots of content or competitors, or your application generates revenue, then Cloudflare Enterprise is the tool for you. Enterprise CDN caches your content as close as possible to your visitors, optimizes it on the fly and serves it on priority basis over all other Cloudflare traffic.
It also includes advanced security features that the free version does not, such as Web Application Firewall (WAF) advanced rules that block hackers and mitigate attacks before you even notice. There is also DDoS protection with priority, PCI compliance, free wildcard SSL, and more.