If I'm looking at ~10,000 users, I will go with Ruby on Rails (ROR) because I have a few years of ROR experience and I can get things done faster. ROR handles m

If I'm looking at ~10,000 users, I will go with Ruby on Rails (ROR) because I have a few years of ROR experience and I can get things done faster. ROR handles many things for you (like security) and there are many gems out there to help you get things done that otherwise would have been complicated (devise for generating users database). When you are done, push it up on heroku and you will have a solid product. If your site is very real time (chat, real-time data), I'd look into meteor. They are a framework built on top of NodeJS and its built from the ground up to be real time. Like ROR, they do many wonders for you app (security) and has built in user authentication system. If you are looking to build the site for a learning experience and want to learn how the web works and build everything from the ground up, go with NodeJS. Install packages yourself, tinker around with security, etc. Its a great exercise.