It’s slow as hell and even the simplest things in their UX takes multiple clicks. Like resolving a ticket should be as simple as dragging it to done column but JIRA makes brings an additional popup for resolution type. Annoying UX like that.
Definitely a big opportunity to make a dent here.
Feedback: don’t use Atlassian JIRA’s screenshot on the main repo page. Have a screenshot of the UI you’ve actually built.