We just updated Jira at my job, it feels pretty snappy. It has always felt reasonably smooth to me, but I have also only been using it for about 2 months.
The most things in JIRA I need to click probably at least 5 or 6 things to do something. So I didn't necessarily mean it's slow as in clicking on something takes forever to load (though I've seen that happen on self and Atlassian hosted versions of JIRA) but that it just simply takes way too many clicks to do anything in JIRA (except maybe creating an issue since that's always at the very top). In my opinion at least.
