TO ALL DIGITAL ARTISTS: Cintiq 21ux Vs. 12wx?

I'm a Game Art & Design major in college and I have a couple digital painting classes, my friend works at Insomniac Games (Ratchet & Clank) & Is a 3d artist. He uses the 21ux's there at the company. I was wondering if It's even worth getting a 21ux and if people use it for Maya Zbrush and a bunch of other programs. Also, I can't bring it in and work with it in class =/ so... that will suck.