[andypants]

It's not JSON, it's BSON. BSON supports more data types, which are needed for a proper database (such as object IDs, longs, doubles, binary data, references, etc.)

You still need a driver and a bson serializer if you use node.js.

[viscanti]

Sure. But it's certainly easier than most other languages. It's not a great reason to switch for that, but working with Mongo is fairly trivial in Node.