Wow, it's really nice to see an article that isn't a "my language/platform of choice is better than yours" rant. I'm especially surprised to see a Java developer embrace node.js so whole-heartedly.
Node is a special purpose evented system, not for general web site creation, though it can abused to do both.
But I would not compare it with Grails/Life/Spring or Rails/Django/Cake/Symphony etc...