Aren't Drupal and Node at vastly different levels of abstraction? I gather that Drupal is vaguely akin to a souped-up WordPress while Node is a fairly low-level server.

Did you start writing lower-level code, or are you using some sort of extensive stack on top of Node?

Exactly the same move here. We created ~2 dozen drupal sites and went to node.js in early 2011. There was about 4-5 months of learning curve, where we almost went back to drupal. The low level of abstraction in node.js resulted in some loss of productivity during that time. But over that time we stitched together sufficient little pieces of CMS capability that we have now fully recovered. And the benefits of working with node.js and javascript over php is pretty huge.

Our only regret now is not having moved to node.js sooner.

Having worked quite a bit in the Drupal world, since 4.6, I demand more info :)

Node and Drupal are completely different beasts. Did you write a new system built on Node, that duplicates what you get with Drupal? Is any of your code public, so others can look into it?

Are you the guys who created OpenAtrium?