While I agree that Jira is slow and generally a total pain to use (I can almost hear the JVM roaring 8000km away), I think Github is the contrary: fast with very good UX.

it is odd that JIRA is so slow, and I doubt it's due to the JVM. Clubhouse is built using clojure and is delightfully fast to use. (not affliated, just a Dev who has used mingle, Jira and clubhouse)

Admittedly I havn't used Jira for about 6 years, but I don't recall it being particularly slow, at least if you give it decent hardware to run on (this is on-prem, so not sure how the Cloud editions go).

If you're talking about process aspects, well.. that's also a business process thing, as to how much information PMs/etc want.

Cloud JIRA is so bad that Atlassian is pulling an Oracle and adding contractual clauses to forbid people from talking about it.

I used it 6-8 years ago on-prem. I remember hearing it needed a rather beefy server and I don't remember it behaving particularly fast but it wasn't particularly slow, either. My jobs in-between didn't use Jira, but my most recent one uses the hosted version--it's very, very slow. What's annoying is it doesn't seem to cache either, so a second reload or navigating around is also slow.

I only read this in passing, but I heard it's the growing pains of changing a codebase intended to run on a single-server and trying to rebuild it into "services" that scale.