I like the fact that Node comes with a small core. I'm tired of vast, bloated, incomprehensible libraries that are going to take me more time to learn how to use than they'll be worth.
I'm not trying to put node down, I'm a fan (switched to Go for most of my needs about a year ago, though), but this argument (small core so less to understand) just isn't valid if you're going to do anything more involved than learning the language and writing hello worlds.