The Most Advanced Ruby and Rails IDE
RubyMine includes bundled evaluation license key for a free 30-day trial.
Due to differences in RubyMine and IDEA release cycles sometimes new features will be available in RubyMine earlier than in Ruby plugin.
Ruby plugin for IDEA supports Java/Ruby integration for JRuby code, but doesn't have RubyMotion support (https://youtrack.jetbrains.com/issue/RUBY-13640).
Works on Mac, Windows and Linux