It's a menu. So I can't really say one is better than another -just different.
In 1 scenerio, I setup PHPTICKETS because:
-a single user
-automatic prioritization
-immediate phone support was unlikely/not probable
-wanted tickets to be created by emailing an email address
-simple interface (open/closed)
-wanted a public way to create help tickets via a web page without a username/password
In another, I setup CERBERUS because:
-mulitple users in multiple departments
-abiltiy to assign a single task to mulitple people at the same time
-ability to scale as dept grew
-highly customizable dashboards per user
-needed due dates
-wanted a project that was supported (and continually developed) by someone so that the project wasn't left dead in the water (like so many good projects) to prevent having to find something else later on.
I haven't review most of the others in a long time.