As far as ticket / issue tracking systems and wikis go their products are quite decent.
JIRA has its quirks but it's very flexible and customisable. Its UX is also quite ok for such a complex piece of software. Keep in mind they're competing with stuff like SharePoint and downright UX atrocities such as HP ALM.
Confluence is among the best enterprise wikis targeting end users (i.e. users not familiar with Markdown), too.
HP ALM is awful. The biggest issue is that you needed to install it on the client machine to be used as a plugin. I would rather have Atlassian products than HP ALM and Clearcase!
JIRA has its quirks but it's very flexible and customisable. Its UX is also quite ok for such a complex piece of software. Keep in mind they're competing with stuff like SharePoint and downright UX atrocities such as HP ALM.
Confluence is among the best enterprise wikis targeting end users (i.e. users not familiar with Markdown), too.