I am using Jira + Atlassian plugin in the past 2 years and I am very happy with the production.

I have a feature suggestion:
add counter to each user story (in work screen) that count down the days from the moment user story is in progress. for example user story with 4 user story point will show the number 4 when it start to be in progress in the next day 3 and so own.

I think it will give a view to the team how much they spend on the user story against their estimation