Functionality
When it comes to working with JavaScript, if you’re just editing a few files, you’ll want validation to stay out of your way. Or when working with a large project, you’d appreciate good IntelliSense and code navigation capabilities. You want to be able to build your projects using the same tools you use in production, and finally, if you had an easy to use debugger, perhaps you’d use it more often!
Having accurate type information is vital to providing good IntelliSense, navigation, validation, refactoring and even formatting capabilities. CodeMix achieves this by using type inference, JSDoc or even TypeScript declaration files, often available for key JavaScript libraries. RHDS uses Tern and Tern modules for the same, while STS is stock JSDT.
IntelliSense
While RHDS can take a while to provide suggestions (see chart above), it eventually gets there. CodeMix provides suggestions instantly in most cases, and has the added benefit of providing parameter hints as well.