When comparing Perforce vs Fossil, the Slant community recommends Fossil for most people. In the question“What are the best version control systems?” Fossil is ranked 3rd while Perforce is ranked 9th. 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 Multi platform availability
Pro Central repository/server
There's a central repository and a clear path/protocol how to reach it.
Pro HelixCore
Helix Core for GIT large files is free for up to 5 users.
Pro Solid workflow for binary files
Perforce has shown itself as very capable when it comes to managing binary files. That's why it's still the go to version control system in game development.
Pro GUI and Visual Studio integration available
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 Closed Source
Con Does not work offline
You must be connected to the internet to do anything useful. Although, there is a Git <-> Perforce bridge that sorta solves the problem.

Con Centralized
Branching becomes a pain due to its non-distributed model.
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.
