[AdamHeard]

Let's try to keep the anecdotal evidence out of this thread in terms of pro/cons. (not talking about you Eric).

It seems some of you are thinking of some of the pros/cons of a 6wd in general and randomly putting them among the two groups.

In my opinion (assuming the traction wheels have a mu of 1.3, the omni's are AndyMark's with 1.0, the rocker has a reasonable center wheel drop, and the non rocker is 4 traction wheels with two omnis with no center wheel drop)

These are just rocker vs. non rocker w/ omnis. The general pros/cons of all 6WDs are left out.

Rocker Pros;
Well, your overall traction will be higher as all load bearing wheels will have a higher coefficient of friction.
Much more difficult for opposing robots to disrupt you.

Rocker Cons;
Well, if the center wheel drop is wrong you can have a robot that rocks really bad. However, this is more of a specific problem than the overall design. Our 2007 base had 6 high traction wheels with about .15 drop and it not only turned very well, but didn't have any noticable rock.
Will probably turn slower than with omnis, but I don't think turning speed is an issue.

Non rocker Pros;
Well, it it will turn faster if that is what you want....

Non rocker Cons;
It will be easier for other robots to turn/disupt you.