While poetry is the way to go today, I've got my eyes on pdm. https://github.com/pdm-project/pdm
Pyproject.toml is a pep standard so it will be easy to move around tools.
Very different. Requirements.txt only handles dependency packages, and only handles on kind of dependency (no dev/release distinction). pyproject.toml does dev/release deps, it has package metadata, it can configure all your lint/test tooling, and it is extensible with plugins.
https://python-poetry.org/docs/cli/#run