Not only does it cover the various features of Rails, in it you build a real life app: a simple Twitter clone. Once you've finished the Hartl tutorial, you'll know how to build an app in Rails, how to write tests, how to use version control and how to deploy it to Heroku. It covers everything to build a web app with nothing missing. All in all, if you don't know much about software development (as opposed to programming, which I know you're experienced at) then I can't put enough emphasis on how great this tutorial is.
Others have suggested Django (a great framework that I've used too and love) as you know Python. That does make sense. If you're really confident in Python, perhaps you should pick Django. But Ruby won't take long to pick up either and I can assure you - the tutorial is worth it.
Finally, there are lots of other new frameworks, including client-side frameworks, that might be helpful too. I'd wait though for a bit. For the moment, you just can't go wrong with Rails. Years later, there's still just as much a demand as ever for Rails developers and it's a solid base that, once learnt, should serve you well for many years, whether you're building small projects for fun or large projects professionally.