I haven't noticed JIRA cloud being that slow, but maybe that's because the team is small.

Did you start to experience performance issues as team size increased? Did you have a lot of issues or data held in the issues? Or was there another issue that you think led to the slowness?

I'm interested in your insights as we went with JIRA initially, since it was pretty much the gold standard and we thought it would scale nicely as we added team members, but if it is not going to do so, then it may not be worth the JIRA premium.