one awesome thing about these kinds of drives is that they can have increased maneuverability without having to build a complex swerve drive system (having motors to rotate the wheels. You can spin very easily and many teams use a 4 wheel configuration of this idea. I know we did, and about 5 or 6 or the Waterloo teams did too.
I think
This is 229's version with wheels at the corners. Billfreds is simpler i think, but it may need casters or whatnot. I think this is a solid design by the way.