The central problem with JIRA is that, once you've gotten beyond the overly customizable functionality and difficult-to-reason about permissions, and once you've managed to avoid organizations that go too far off of the deep-end and once you've finally found a happy simplicity in a kanban-ish board,

once you've done all of that, it is still unbelievably, unjustifiably, just incredibly and amazingly so very very goddamn slow.