hmmm, good question. Almost immediatley you would want to say veteran so you seem to have a good chance on winning. Yes, veteran is good especially for experience, but I believe it would also be fun to be on a rookie team! Do ya'll remember your schools first year??? I bet it was the bestest funest ever! hehe
While veterans have fun experimenting with what they've learned and crashing old robots, rookies get to joke around a whole bunch and pretend to not know what they're doing (even though they do! hehe)
I think both is great! It's fun either way and each is fun in their own way! Like I said, great question! ^.^