I just can't wrap my head around complex JavaScript-based projects. I was working on a PhoneGap-based mobile app last year and it was a pain to develop and debug.
I've been hearing lots of good stuff about node.js though, so I might have to give it a try eventually and that tutorial looks neat.
The fact that Node has such a vibrant community with more modules than even Java at the moment has definitely helped.
There are a lot of modules for whatever you can dream of, from ORMs to communicating with Arduino or your router. That's one of the reasons I love Node so much.
People's familiarity with JavaScript definitely helped - unlike with Rails when it was first getting big, you didn't have to learn a new programming language in order to start working with a new framework.
with node & express I get serious flexibility. Some great examples in this tutorial, getting started with streaming & real time apps with some pretty minimal code. Nice.
I've been hearing lots of good stuff about node.js though, so I might have to give it a try eventually and that tutorial looks neat.