When comparing Mantis BT vs Fossil, the Slant community recommends Fossil for most people. In the question“What are the best self-hosted bug trackers?” Fossil is ranked 3rd while Mantis BT is ranked 17th. The most important reason people chose Fossil is:
Fossil includes source code management, bug tracking, a wiki, and technotes. It even includes its own web server, though it can fairly easily be incorporated into other webservers.
Specs
Ranked in these QuestionsQuestion Ranking
Pros
Pro Open source
MantisBT is a free and open source bug tracker.
Pro Light
Really light and simple. Good for simple management.
Pro Very complete
Fossil includes source code management, bug tracking, a wiki, and technotes.
It even includes its own web server, though it can fairly easily be incorporated into other webservers.
Pro Self-contained
A Fossil repository is contained in a single file.
Pro Cross-platform
Fossil can run on Linux, Mac, BSD derivatives and on Windows.
Pro Very easy to configure as self-hosted
Single, stand-alone executable, including web server.
Pro Needs very few server resources
Since Fossil is a distributed VCS on top of being a bug tracker, it needs very few server resources.
Cons
Con Little integration
Supports little integration with code repositories, and CI servers
Con Too simple
Not powerful enough for complex management.
Con No documentation can be found in the installation files
The files that are included with the installer or the files that come out of the box after a fresh installation don't include any documentation.
Con Only a web interface or CLI
Fossil's bug tracker only works with the web interface or the command-line interface. There's no native GUI client supporting it.
There are some independent GUI clients out there, but none of them support Fossil's full range of abilities.