Please note that features for JIRA Server and JIRA Cloud may differ due to the platform specifics.
Detailed Build Statistics
With JIRA TeamCity Integration, detailed build statistics will be always available for you directly in JIRA. After you install and configure the plugin, you will see the TeamCity tab on the Project, Issue and Version pages in JIRA.
Thus, for every JIRA project, issue or product version you will have a complete list of builds associated to it. The list contains the information about whether the build is successful, its start date and time, duration, etc.
Links to TeamCity
The add-on shows generic information about build parameters and allows you to click links in the build list to open TeamCity with detailed build configuration or build results.
Now the The add-on also supports work with multiple TeamCity servers, so you can much more easily and efficiently track multiple projects and build activity in each one without leaving JIRA.
Build Change Log
You can always see what exactly changes and new features your builds include. Since TeamCity compiles builds from the files commited to the version-control system, all committers will need to log messages that describes their change to the code.
These messages will be shown right in the TeamCity tab in JIRA giving you a better idea of what has been completed for your JIRA projects.