Node has a wealth of open source projects available for use in your project, saving you time and providing cutting edge features. The NPM utility is similar to Python's PIP and PHP's PEAR. You can download, track and integrate open source packages without worrying about compatibility or tracking versions of software inside your own code repositories. Upgrading every package in your project can be as simple as a single command.
Node can let you reuse the same code that will be running in your customer's web browser on your servers. This means your programmers only need to write code once and you can distribute that code on web pages, mobile applications and browser extensions or desktop applications. This can save a significant amount of time especially when using Test Driven Development as you only have to have one testing environment and maintain one set of tests.
Node is still a relatively young project and can change drastically or have minor issues in newer releases. You also have to be familiar with the packages available via the NPM utility that is used to install packages that provide common features needed for many projects. Some of these dependencies can also be very young and unstable. While npmjs.org has a wealth of information about each package, just the version number or popularity of a given package doesn't always tell the full story. It's important to partner with people who know which projects you can count on.