That's surprising -- my impression has been that one tradeoff with Node.js vs. frameworks like Rails & Django is a lot more work to implement functionality they ship with out of the box -- it works at a much lower level.
It also tends to be slower going for a while as you get accustomed to the non-procedural approach.
We were able to develop this quickly for a couple of reasons. One was that we already knew rails. We used a lot of rails patterns throughout our project. Any rails dev who looked at our directory structure would be feel at home. Another reason was that we had a good understanding of our domain. We were able to anticipate many features and tasks that would have been been expensive (time-wise) to implement later. Another reason is that had 2 week release cycles with demo-able features at the end. This kept things moving at a good pace.
And of course, we have high caliber staff ;-)
So your opinion, so far, is that it is easier to modify the application, after it's launched, in Rails than it is in Node?