It's my favorite build system. A big advantage is automatic dependency tracking. It picks up unspecified inputs and automatically rebuilds anything further down the dependency tree. It also knows how to clean up files that it no longer generates since it understands you removing and adding build steps.

I can do huge refactors and it cleans up files without any additional work from me. The filesystem watch automatically builds things so I never have to run it directly. I use it on my production server when deploying since it's 100% accurate at incrementally moving between different project states.

There are definitely some disadvantages, you have to work around its syntax and limitations. For complicated build functions I've written the config in Lua and it works fine.

I tried out Tup, and thought it was really impressive and probably great for people who need to write C, but not suited for what I was trying to do.

The project I tried to use it on was a before/after comparison of the results of some development work to an energy model. So, a couple of my make targets cloned old and new versions of the repo.

Tup doesn't like you to create directories, and wants to track every file that comes into existence and check that it is either a) a declared output or b) deleted by the end of the job. It really didn't enjoy trying to process a whole Git clone operation.

I really like it, but I don't know if it's worth the hassle. For example compared to ninja it isn't that much faster and it's missing a good configuration system anyway. Definitely better than Make though.