Some of the Disadvantages of Cloudflare (as of now) :
Setting up a Sub-Domain with Tumblr is not possible
With Cloudflare, setting wildcard subdomains is not possible
Not enough information on data that is cached, which leads to misbelief of whether the things are really getting cached or not.
Does not seem to act like a real CDN, when i pull the website in asia - instead of getting data from singapore datacenter, i get data from california datacenter
5 As earlier said, security blockade is a big concern. you might be loosing a lot of pageviews as most of the peoples networks or computers are infected
Since all your traffic goes through their servers, depending on the options you choose the Cloudflare service:
Inject javascript into your code while returning pages.
It modifies the code of your pages.
Modify the http headers of your pages. For instance, it adds a cookie entry.
Cloudflare imposes HTTP/2
Cloudflare imposes IPV6 settings
IP addresses can get a bad reputation compared to other IP address.
Cloudflare can:
hurt your website SEO
block your website
slow down your website
make your website crash. (issue with real IP, https link issues)
make your website inaccessible.
Monitor all your visitors & gather information about them
also CF will very often send captcha for users which annoying
Edit: Since I posted the answers, most of the disadvantages above have been solved. Kudos to Cloudflare team…
But I would still like to address the concerns that might still be valid:
This is because anycast isn’t always optimized for the best route. It really depends on how ISPs peer with each other and whether or not they directly peer with CF.
Thank you so much for clarification. I am gana install it in my wp website and will use the free version. Do you have like a video guide on how to best configure cloud flare.