If you're an expert in make and already have a Makefile, I would not recommend switching to just for that project.
The benefit of just is that it's designed to be a command runner, whereas make is designed to be a build tool. justfile syntax is much simpler and more ergonomic. It also has nice features: Private recipes, submodules, recipes that you can specify to run only in a particular OS (we use the same justfile for both Windows and Linux), writing your recipes in a language other than your shell language, and many many other niceties.
A new user can start doing "advanced" stuff in just in a couple of hours. They'll take a lot longer if trying to do it via make.
The benefit of just is that it's designed to be a command runner, whereas make is designed to be a build tool. justfile syntax is much simpler and more ergonomic. It also has nice features: Private recipes, submodules, recipes that you can specify to run only in a particular OS (we use the same justfile for both Windows and Linux), writing your recipes in a language other than your shell language, and many many other niceties.
A new user can start doing "advanced" stuff in just in a couple of hours. They'll take a lot longer if trying to do it via make.