Granted you know Ruby well and like coding in it. The amount you need to learn if you don't know RoR or Ruby is huge... You might get some stuff running fast copy pasting some example but claiming that it is all super easy to do anything meaningful is misleading.
This was exactly my experience. I struggled building with Rails, and every day was an uphill battle trying to learn the machinery. I switched to Node, and feel my better. My structure isn't nearly as pretty, optimal, or efficient now, but I'm actually learning the base concepts and understanding what I'm doing.