Cloudflare was able to deflect 2 massive DDoS attacks. During the March 2013 attack on Spamhaus, they were able to absorb a peak 120Gbps attack that lasted 4 days, as well as a 400Gbps attack in February 2014.

Their track record shows their ability to protect against DDoS attacks in practice.

Cloudflare protects over 2 million web properties; with such a large and diverse set of customers, they can pick up on trends very quickly. While their competitor, Akamai has larger customers, they have fewer customers in total, giving them a less diverse data set for protecting smaller customers.

Cloudflare is pretty hands off when it comes to how much customization is required by the user. They take an approach of handling the hard stuff for you so you don't have to manage any security rules for yourself.

Cloudflare uses servers provisioned by Quanta, the same company that makes Facebook's servers, to create custom hardware, specifically tailored to load handling, and security applications.

CloudFlare offers a free plan with basic DDoS protection and promises to always provide a free service with at least the feature set that it has today. More advanced DDoS protection is available for the higher plans, which can be added as your needs grow.