You are frustrated with coding Apex in Eclipse because it is slow or you are coding in the browser 😦 not the best thing when you close the window and loose all your code…to the rescue MavensMate. MavensMate is an Force.com IDE is an add-on project running on Sublime Text 2. I have been using MavensMate for a while now and have seen a great benefit in time, auto completion (less time typing) and just easier all in one experience from coding, testing to deployment.
The following functionality is awesome:
1. Code completion
2. Quick code search
3. When code is saved, validation takes a few seconds (compared to Eclipse it is faster)
4. Testing code inside MavensMate is a breeze and you can play games while waiting for it to complete.
5. Direct integration to your Git repository.
6. Create new files (Apex or Visualforce) from inside a Project
7. Easy to run Anonymous Apex code.
8. Easy to deploy code to different SFDC environments.
9. Manage your metadata between environments.
10. Great documentation to explain how to use MavensMate.
I recommend MavensMate to all serious Apex developers. Follow these steps below to get started:
https://github.com/joeferraro/MavensMate-SublimeText
Thys Michels Blog 
Sounds great IDE, but seems no luck for Windows developers as the plugin for Windows is still in development.