My Team 61 uses tracks and has for 10years now. We use them becuase there reliable unless you have to much power then you rip them.
http://www.valleytech.k12.ma.us/robo...s/MVC-671S.JPG
Not many teams have done that =)
http://www.valleytech.k12.ma.us/robotics/
Click on photo galley and you can see how we have inproved them year by year.