It's still work in progress, but compared to trello:
- it has a flexible tagging system which combined with the search can provide some nice filtering views (on the board view the filtering is done client side and it's applied in real time on new or updated content)
- use of github flavored markdown for comments and description (and code highlight)
- multiple login are supported (at the moment we have oauth2 for google/github/bitbucket, mozilla persona, ldap)
- support for categorizing the tickets in milestones (and a dedicated milestones view)
