[jacques_chester]

Tracker is very opinionated and is deliberately trying to not be the be-all and end-all for software projects. It's really closely tuned to how Pivotal works: XP with Lean trimmings in small teams with a product manager, designer and engineers.

The downside is that because it is deliberately limited, now and then you will find that you sorely miss something. Often those missing features are recreated with conventions around tagging or release markers. But tagging conventions are not the same as a first-class feature, for good or ill.

JIRA is massively more featuresome and flexible. These days it's grown into a workflow middleware which comes with a bug tracker as the first application installed. For some organisations that will make more sense.

Disclosure: I work for Pivotal, but not on Tracker.