They do work, but every time I entrust my websites to them, I encounter problems. Usually in the form of downtime, but also DNS problems and other service-related issues.

An incredible feature set at the free level, with fantastic CDN and firewall control. They're constantly working to bring new options as well (such as domain registration!)

Wide range of online CDN tools, most available for free, and some extras available for a reasonable price. Access to a worldwide CDN network for low cost and no difficulty

After having used Cloudflare for over a year, I'm happy to know that they are continuing to grow. I feel that their role as a CDN has improved both the speed with which my website loads to viewers as well as security they provide for the backend of my site. Within the past year, I was witness to live DDoS attacks on my site thru 3rd party security software. When this took place, I was able to change one setting ("Under Attack") on Cloudflare which effectively locked down my website to the attackers and yet still kept it free on the web for others to use. Once the attack was over, I just changed the setting back to normal and all was good. One more thing to add, because of the way in which a CDN delivers, it was very convenient to be able to "clear the cache" at Cloudflare after making changes to my site. More importantly, you have the option of clearing just the cache of the specific page you were working on.

Great CDN Service and great for keeping a copy of your site online when it goes down