Maintained by a big company.
Simple installation process.
Front-to end exposure (repository, issue tracking, feature management, etc.).
Enormous user base with lots of exposure.
Excellent documentation and support.
We can take advantage of the 10 user certificates of confluence and green hopper. Will be good to use when the project is going to start.
Room for Improvement:
Generally, customization, granted that it is done only at system productions state, is hard and time consuming.
Most of functionality that is not required for use of system, cannot be deactivated; you need to dig through all superfluous stuff, in many cases.
Even though JIRA documentation is immense and solid, filled with tutorials, you really need docs, to use JIRA, the system is so complex that you need to read docs almost for every customization task and even then, some views are hard to understand.
Disclosure: I am a real user, and this review is based on my own experience and opinions.
May 05 2013