If you are familiar with Python then you should use PyPy + Tornado. It is more beneficial, productive, and maintainable than using Node.js
Node.js claims that it is faster than Python but Python provides PyPy+ Tornado to overcome this disadvantage.
Python is also using a lot of internet companies now a day i.e. Quora, Nextdoor, Youtube, Pinterest, Slide Share, Apture, Disqus, Mochi Media etc.
Node.js Advantages over Python
Following are some important features which make Node.js more preferable over Python.
Node.js can be used for both client and server development.
Node.js uses Google Chrome’s V8 engine which makes its library very fast in code execution.
Node.js is well suited for asynchronous programming.
Node.js is getting popular day by day. It is now using a lot of companies like Google, Microsoft, and Apple etc.
Node.js uses non-blocking I/O throughout so, it is the best option for creating a real-time web application. For example: chat application. On the other hand, Python is the best option for creating CRUD based Applications