Ask HN: A (free) Rails editor for newcomers

I recently made a career move and ended an eight year run of Lisp development. As you might have guessed I used Emacs exclusively.

On my first week in Ruby I've been trying out different editors to see which suits me most: Emacs, Atom, and Sublime.

I would like to know which other editors do you rubyists suggest to newcomers'?

(Thanks in advance. :-)

Edit: Although I'm looking for a free editor feel free to mention paid ones if you don't like any of the free ones.