I know many PHP and Node.js frameworks but none of them is as simple as Meteor. Even front-end developer can write full-stack application in Meteor. You just need to know JavaScript, MongoDB, HTML, CSS and you will be able to build Meteor app.
Meteor's code does not look like code of classic Node.js framework. It's an abstraction of Node.js and it's more beautiful.
For example client code consists of helpers, events, sessions and templates...