We use them both. Jira is used for 3000-odd developers worldwide on tens of projects, fixing as many as tens of thousands of bugs daily. It's flexible to integ

We use them both. Jira is used for 3000-odd developers worldwide on tens of projects, fixing as many as tens of thousands of bugs daily. It's flexible to integrate with our toolchain and source control systems. Managers like it because it can easily throw up a load of stats and graphs on a single page. As a user I like it because it does everything I need it to. Confluence is used here, again for worldwide multi-project deployment. Mediawiki is also used but rarely - when starting a new project developers are given the choice and Confluence is the preferred wiki system. Managers love it because of the excellent Word editing/export features. I like it because it does everything I need it to. Downside of both: the searching on either system isn't that great. It's more IE-friendly than Firefox-friendly.