It is obviously possible to develop useful apps in JS. What tools can be recommended to ensure productivity & quality?
We like to say you can start programming with a simple text editor and a browser, and I do all my coding that way for the book so I know how it will feel for someone programming that way.
That said, yes, there are some good tools emerging that will aid in development. I have heard good things about WebStorm although I haven't used it myself yet; I primarily use TextMate and Coda. It's certainly true that once you get used to a certain tool, it takes effort to change!
I'm sure others will chime in with their tools and processes.