We've found JIRA to be the best option for our small (5 person) team. We enjoy the ubiquitous integrations, powerful project management tools and reliability. Keyboard shortcut support is fantastic.
I would warn that (as of 1.5 years ago), JIRA Cloud is very slow. We've since moved to JIRA Server and solved the speed issues.
I would warn that (as of 1.5 years ago), JIRA Cloud is very slow. We've since moved to JIRA Server and solved the speed issues.