Ask HN: Web frameworks for SaaS applications

I'm a Java/Python programmer with some SaaS ideas for the Danish market.

I have no experience in web development beyond HTML/CSS (+ Bootstrap), JavaScript on the client-side and some Node.js on the server-side.

Which web framework is ideal for developing SaaS applications like Basecamp and Harvest?

There are so many frameworks out there like Rails/Django/Meteor and the MEAN stack so it's pretty hard to decide on a final framework.

I would love to learn a new language like Ruby (for Rails) but the Meteor framework looks promising but more focused on real-time stuff.