[Marc P.]

Pros- Students continue to learn about how their robot works, what it's capabilities are, what needs to be changed come competition time. Practice robots can be an invaluable source of practical experience as to how the real robot will perform, and can help greatly in training students/pit crew how to deal with any problems that may come up in the heat of competition.

Cons- Gives teams with more resources a potential advantage over other teams, which some may consider unfair. Not all teams have the funding or resources avaliable to build two robots, and because of all the pro's listed in this thread, teams with practice bots have a leg up on the competition. This isn't so much a con for the team itself, but a con for other teams who can't build one.