Offensive Robot
Pros:
Can shoot(I'm assuming

), which is helpful to winning, you know?
Funner to build
If it's really effective at shooting, easiily will be chosen for elimination
Cons:
1. Must sacrifice a little low center of mass and time and might not be able to balance
2. Probably will be overused a lot, might not be good if you're trying to get chosen for elimination rounds.
3. Less time to perfect, you have lots of precision things to get right(programming and mechanical)
4. Might not be able to actually score because of opponents' defensive robots.
Defensive Robot
Pros:
1. Easily chosen if effective because it can essentially allow ur own team to score while they can't
2. Easy to build, more time to perfect
3. Will probably be easier to balance on bridges
Cons:
1. Can't shoot, which can lead you to quite a problem if everyone on your team is defensive/balancing only and you guys don't score while the opponent does. Even if you manage to balance with the opponent, they have still technically WON the match.
2. Boring to drive and stuff
3. hard to find the right drive. You want to be effective at blocking yet be able to cross the bridges/bumps to get to the other side