Why?
It’s free.
It provides asynchronous, event-driven API’s for all robot hardware.
It supports an MVC-like abstraction and encapsulation system for clean, elegant code.
It’s easy to learn use, with loads of documentation and active support.
It has a simulation/emulation environment for time away from the 'bot.
It’s been in use on multiple robots for over 1.5 years, with lots of utilities to make development easier (network API, file logging, switchable modules).
@lineskier: yes its running on a robot built in the last 4 days, using the 2011 SDK and hardware. Robot has all the normal things (4CIM drive by jaguars, line followers, camera, accelerometer + gyro, encoders etc).
@jhabersat: the way the “emulation” works is by taking the code that you write on top of the framework, and simply not making calls/importing WPIlibJ (which is what the hardware is dependent on). Instead, these hardware bindings are made to the EDemoBoard part of the Sun SPOT hardware platform, which has a hardware emulator called “Solarium”. Obviously there’s no physics simulation, but it does allow you to run your code in some capacity without the actual robot. Get the silly runtime errors out and such.