I've been using ST3 for Ruby/Rails development. I was particularly interested in the "go to definition" functionality. I am a regular user of RubyMine and while code inspection is it's strong suit, the editor never felt responsive. Hence the ST3 trial.
The method jumping functionality is very good. Not on par with RubyMine; e.g you can't jump to an ActiveRecord method or any other 3rd party gem. But for navigating your code base, it reliably finds method definitions across the whole project and find them quickly.
It's not on par with RubyMine, but it's still a solid addition.
You can search through any files that are in your project workspace. When you start a project, just "Add Folder to Project" and include the ruby gems directory and the ActiveRecord source directory.
The method jumping functionality is very good. Not on par with RubyMine; e.g you can't jump to an ActiveRecord method or any other 3rd party gem. But for navigating your code base, it reliably finds method definitions across the whole project and find them quickly.
It's not on par with RubyMine, but it's still a solid addition.