The comparison is not entirely correct. The difference between node.js and express.js in the level of abstraction:
- Node.js is a run-time environment for building server-side event-driven i/o application using javascript.
- Express.js is a framework based on node.js for building web-application using principles and approaches of node.js
So, if you write web-application, you can try to use Express.js. In all other cases, it does not suit for you.