The thing is, cloudflare does not really protect that well from much. If your site is being attacked, it just puts up a captcha page, this does not help anything really.. Remember twitter's fail whale? Fail whales are great, or also known as a "sorry page", all you have to do is serve this directly from haproxy RAM and your customers will be happy to know that 1) you're down, and 2) you're sorry, and 3) you're working on it.
Any DNS provider, that can mitigate DDoS DNS floods or etc, that's all just built into most DNS providers now, so cloudflare really has no purpose other than taking your money and selling your data to bigSurveilance.
