While we had T38 to deal with CloudFlare and T48 for cache policies, I think we should drop both of these in favor of moving Fastly in front of our systems at large. In general it just seems to perform a lot better; for example, using the Fastly CDN URL for Phabricator itself (logged into my account, viewing the homepage, which has a lot of stuff for me, both static and dynamic):
CloudFlare on the left, Fastly on the right. In general I've never noticed it as slower, and in scenarios where there was some lag, I noticed Fastly being up to 50% faster in overall load time. So I think this is a win to deploy at large, although we can of course migrate off CloudFlare incrementally as we need to.