I haven't gotten to use FogBugz so I can't compare the use of the UIs. AJAX would be really nice, although I haven't had any performance issues. We replaced M

I haven't gotten to use FogBugz so I can't compare the use of the UIs. AJAX would be really nice, although I haven't had any performance issues. We replaced Mantis and Bugzilla with Jira at one place I was at, and it was significantly faster than either of them. I'm in love with the ability to very easily create different issue types with different attributes, states, and work flows. That lets us use the same system as a project management tool with release schedules, features, sub-tasks, reporting on hours breakdown by resource etc..., and a customer facing issue reporting/tracking system, and an internal bug tracker, etc... edit--- Also love the great integrations with Confluence, Eclipse, SVN, Hudson, etc....