Having just moved from Jira to YT, the one thing I miss (and really its the only one!) is the tab showing all commits that referenced the issue in the comment. I know that YT will show any actions in the History tab. But it would be really nice to just see all the commits for the issue.
To some degree its there if you use teamcity. But's that a kind of roundabout way to see the commits. Also it requires that a build have been performed.