Mechanum Wheel Sizes

[nxtsoccer]

Hello, my team (4087) recently completed our first FIRST season at FRC. We had a blast and are talking a lot about expanding the size of our team, budget, and quality of our robot for the 2013 season. Anyway, one major topic that my team has been talking about is holonomic drives, specifically mecanum ones for next season's robot. I've been doing some research into these wheels and have found many mixed success stories. At any rate, I found much info online as well as on Chief Delphi, however, I could not find a good thread discussing which sizes of mecanum wheels generally work best. I read somewhere that teams had problems with the 6" AndyMark mecanum wheels deforming and the 10" AndyMark wheels seem very expensive, too large, and too heavy for practical use in FRC. Does anyone have any first-hand experience as to which size(s) work well (movement not too bumpy, resistant to damage, ease of mounting, etc.)? Any recommendations and/or comments are welcome! Thanks in advance!