Node's strength are in doing streaming UIs. Like realtime twitter feeds that push new tweets to the UI the moment they come in. It also does allow sharing code

Node's strength are in doing streaming UIs. Like realtime twitter feeds that push new tweets to the UI the moment they come in. It also does allow sharing code such as client side and server side validation. And if you use require.js you can develop modules that work server aide and client side. Node.js does add new features, it's ease of use is a feature. Server side push used to be more complicated than it had to be. Python has twisted which I found difficult to setup as it required Python skills which I was rusty on and was more abstracted than I needed. And of course server side JavaScript really is great, I don't see how it's that hard to understand two environments. You can't get rid of that they are different environments but they can share much code and does require one less language to use than most web app frameworks.