Unless there is some new feature that locks you of the other three characters soon as pick one, I don't see any reason to play a little bit of Maya and the play a little bit of Zer0 and switch between them casually until you find a play style with one of them that suits your fancy.
If you plan to play online my vote goes to Maya. If you plan to play offline my vote goes to Zero.
Exactly what I was thinking. Maya is a GREAT team player, and 0 is a great single-player character. I'll be using Maya when I play with my friends. --- I have Dysarthria. It's a Speech problem. Your question is answered now.