I tried using Fossil as a DVCS/Project management tool for a class I'm currently teaching - but in the end I couldn't quite figure out self-registration combined with allowing authenticated push in a way that worked for ~25 students without needing much instruction/hand-holding.

If I'd had some form of user-database already, I could probably have gotten it to work with a proxy in front - but for now I've ended up using gogs: https://gogs.io/

I'm not certain I actually prefer gogs to fossil, but apart for working as I wanted/needed without much setup it had the dubious benefit of forcing me to teach my students to use git, along with a rather cumbersome pull-request system (gogs tend to hickup on commits that probably should've been possible to fast-forward, possibly due to not forcing git to ignore white-space).

Dubious because as a bit of a mercurial fanboy, I think git has a frustrating and opaque command line interface, not helped by the fact that a standard workflow uses various "non standard" (as in: the most obvious) commands. Benefit because learning git is unquestionably a valuable skill, due to the popularity git enjoys, in no small part due to github's success.

I'd like to go back and revisit Fossil at a later time, but right now I'll probably spend any time I can find on (investigating) migrating from gogs to gitlab -- as it's turned out that the limits on pull-requests in gogs make it complicated to use with large groups of people new to version control.

That said, I'm a strong believer in combining wiki, version control and issues in a single repository supporting various DVCS workflows.