Some useful features include:
* `npm --save $PACKAGE` - installs a package, adds it to your dependencies list. Python's equivalent is `pip install`, `pip freeze` to get the installed version, and a manual edit of the requirements file.
* Production dependencies & development dependencies. Python either has to use multiple files, or `setup.py`, which is vastly more complex.
* Installation of modules within the source directory - no need of a virtualenv. This isn't always good news, but it's generally pretty useful.
* Recursive dependencies. There's no global version of a module - your dependencies can in turn require different versions of other packages, without clobbering each other.