WebStorm is packed with features you'd expect from an IntelliJ IDE. Some of these features are:
WebStorm offers code completion, suggesting what you might possibly be meaning to type in, which is helpful.
It offers a built in debugger, supporting FireFox and Google Chrome, which is extremely helpful for web development. It helps eliminate the need to switch back and forth between WebStorm and some debugger application.
It has support for external frameworks such as Node, Google App Engine, React, Express, and many more.
As with every IntelliJ IDE I have used, it has a great library of plugins and supports installing plugins from disk.
My favorite feature that it offers is the UI customization, allowing me to use the Dracula theme, which is perfect as I have a hard time seeing on lighter backgrounds.
Another great feature with WebStorm is the ability to commit and push to GIT repos right in the application itself.
While WebStorm is definitely full of features and my go-to Node/JS IDE, it does have some issues and drawbacks.
As with every IntelliJ IDE I have used, WebStorm does have a pretty large memory footprint. It also can take some time to start up.
When accessing multiple projects, each one is opened in a separate instance, which, again, can impact performance.
Most IntelliJ IDEs allow you to import a project from files on a remote server, however with WebStorm this isn't possible. You must first create a local project, then navigate through the menus to find the deployment options, and add the server and download the files. Added servers are per project instead of throughout the IDE as a while, to me, this is the biggest drawback/annoyance with WebStorm.
We had recently switched from using PHP as our back-end to Node and WebStorm helped with the development, allowing us to develop the back-end quicker and more effectively than other alternative IDEs.