Wouldnt' tracks be better if you are dealing with some high-forces on wheels. Where you would eather sink-in too much (than you are carying too much weight!) or wouldn't your coefficent of friction become so much that wheels won't do it? Wheels just place the weight on a point, while tracks place it over a distance. So, in my opnion (sp?) if you some how can "tilt" the goals to get more traction, i say go with tracks. They turn on a dime, and i personally like the experience with them. My team (#5) got feather weight in the finals 3 (?) at GLR, when everyone thought we broke our bar hanging-mechanisim and we didn't hahahaha
, we weighed like 105 or something lbs, and we where pushing bigger, taller, very much heavier robots than us. I say go w/ tanks cuz' of my personal experience with it, and i think the motors will like it better when going straight, especially with a gear-box!!