I solve problems. You can hire 2 developers for the same price, but once you run into an issue none of them can solve, you'll probably understand why 'cheaper' isn't 'better'. And no, I don't write code twice as fast as the others do. I work better, not faster.
I specialize in developing rich web applications in Ruby on Rails (Python is also an option), HTML5 and JavaScript frameworks (Backbone, Ractive). Some other tools/libs I use in my work: MySQL/PostgreSQL/MongoDB, jQuery, Twitter Bootstrap, HAML/SLIM/SCSS/Coffeescript, Git/Github, Heroku.
My background also includes: PHP, C/C++ (system and desktop programming), Qt, .NET/C#, Android development.