You should use whichever had the best DX (developer experience) for your team. If you are doing a massive front-end project, consider yarn if not only because it makes it a snap to go from zero to ready. What some people say about npm being more stable or easier for smaller projects is highly true as well. (not to mention, you sometimes have to install yarn) But, note that official NodeJS Docker images ship with both npm and yarn. If you want to use yarn, put package-lock=false and optionally save-exact=true in your project's .npmrc file. Compare whether you prefer the ergonomics of yarn global add over npm install -g or see fewer meaningless warnings for the specific set of dependencies you leverage.

We use Yarn because it allows us to more simply manage our node_modules. It also simplifies commands and increases speed when installing modules. Our teams module download time was cut in half after switching from NPM to Yarn. We now require all employees to use Yarn (to prevent errors with package-lock.json and yarn.lock).