Pretty sure the captcha can be switched off for enterprise clients (which I presume SO would be).
Regarding caching, SO's caching is extremely aggressive. It's especially problematic when editing answers more than once, because when you click edit you'll be presented with a cached copy of your answer, potentially excluding your latest revisions. So you have to refresh the edit page and then edit the answer.
It might seem like an edge case, and it certainly teaches you to be meticulous about answering lest you have to go through the refresh hell, but it's not what some would designate as 'good UX'.
I am never surprised by SO's reports about how they run their busy website from a mere handful of machines precisely because of the caching they do.
Source:
https://meta.stackoverflow.com/questions/323537/cloudflare-i...