You can develop using ASP.net, PHP and Node.js with context sensitive code completion as well.
I can go on and on describing the features of WebMatrix 3, but I recommend you just visit the website and check them out yourself.
Well, there are several ways WebMatrix can make your life easier when developing for the cloud. To start with, when you create a new WebSite on Azure, you can quickly open it up in WebMatrix for development and then publish it back through the “Open in WebMatrix” button that shows up in the portal.
The second way is when you open up WebMatrix itself, you will be presented with the option to either create a new Windows Azure trial account, or connect your existing one. When you do either, you will be able to directly manage your websites on the cloud from within WebMatrix.
Once you create it, you will be able to work on the local files, then when you save, your changes would be online in seconds!
I encourage you to go and try it out. Happy coding!