[Jared Russell]

By design, a standard holonomic drive (4 omniwheels at 45 degree angles or 4 mechanum wheels) only use about 70 percent of the available power for translation at any given time - simply because the rest is busy fighting the other wheels to stay straight. And that's not even taking into account traction differences.

We quickly ruled out omni-wheels this year because we determined that being unmovable was more important than being holonomic - and we can still spin on a dime. Defensively, yes, it is nice to be able to hover right in front of someone - but you can only be 5 ft tall, and many robots (ours at least) will be able to fire over that easily. Bumping and pushing seem to be the order of the day.