My opinion based on feature and screenshots is that the UX is as shitty as Jira. The nightmare with Jira is this product manager obsession with kaban boards that become overwhelmed once your project become serious.
What's the solution to this? Which app would you recommend to deal with projects that become serious?
It can look a little bit rough, and sure there could be lot of improvement. But it favored efficiency against eye candy design.
It is very easy to have things organized the old way. Having projects, recursive sub-projects.
You can look at your issues at the sub sub project level or at a more global level.
You can easily have list with all the variable that matters. That you can order easily how you need: Who's the rapporter? Who's the dev? Who's assigned to? What is the state? When was the issue discovered? In which version? Fixed with which milestone?
It is very slick, I did not feel a latency like in Jira, the screen is not filled with useless crux, only what matters fills the screen. In a few clicks I was always able to find what I was looking for, set and identify all the affected versions and which one got the fixes.