The end result is essentially the same, yes - all directly requested dependencies, and all of their transitive dependencies, are extracted and installed on disk into `./node_modules`.

Yarn came out at a time when NPM was particularly slow and buggy. NPM has caught up some since then, but I _personally_ still like Yarn better. I find the CLI output more useful, and it feels like it installs in a more consistent amount of time.

You should only have one of them in use in a project at time.

PNPM is another alternative package manager that installs the same packages, but tries to use symlinks to a single globally-cached copy of each package to save disk space. (I believe recent versions of Yarn have an equivalent option, but it's not on by default.)