RubyMine is a great integrated development environment (IDE) for Ruby on Rails development.  Here’s ten reasons you should consider using it:

1. Built-in debugger.  Using a debugger instead of print statements will increase your productivity dramatically.
2. Built-in support for ERB, HAML, HTML, CSS, SASS, and Javascript.
3. Integrates with Git, Subversion, etc.  You can add files or view diffs right from the IDE.
4. Cross platform.  You can use RubyMine on Mac, Linux, and Windows; so if you need to switch computers you can still have the same familiar development environment.
5. Refactoring.  Easily rename a variable or method.  Extract a chunk of code into a method.  Extract a convoluted conditional into a local variable.  This’ll be so easy you’ll refactor more often, and thus write better code.
6. Quickly navigate files.  You can type abbreviated or acronyms of file names, which makes opening the right file lightning fast.  For example, if you’ve got a file app/views/order_line/_line_template.html.haml, instead of typing “_line_template” into the open file dialog, you can use “lt”.  This works for directories too, so if you have multiple “_line_template” files in different directories, you can use “ol/lt” to specify the one in the order_line directory.
7. Run Rake tasks and Rails generators.  Not a huge deal, but being able to run them from RubyMine saves you some switching back and forth.  You also save a bit of typing with autocomplete.
8. Quickly run your unit tests with a hotkey.  If you’re working on a unit tests, there’s one hotkey to run it and show the colour-coded results right in RubyMine.  There’s no need to switch into a console and retype the test name to run it.
9. Have your unit tests run faster.  RubyMine has built-in support for Spork, a gem that makes running your unit tests faster by pre-initializing the Rails environment.  This makes a surprisingly big difference; you’ll be able to run a test in about a second.
10. Their development team moves fast.  They were one of the first to support Rails 3.0, and they respond quickly to bug reports, so you can reasonably expect they’ll stay up to date.

RubyMine isn’t free, but at $69 for a developer license, it’s not enough money that anybody who is serious about coding should hesitate.  They have a 30-day trial, so give it a try now.  (We’re not affiliated with RubyMine in any way other than me being a fanboy.)