I find it similar to connect/express http://expressjs.com/guide.html but a less tasty DSL and nothing new, or am I missing something? I'm sure one inspired the other since the API is strikingly similar (app.use app.get etc), strange that no comparison is given. Anyway, kudos to the devs for free software!
Having worked with Node for a while now, I can conclusively say it's difficult to say you know it well without building your own framework. Even if you end up with something similar to another framework it's still worthwhile doing just for the educational aspect.