It depends on your strategy, but:
Pneumatics:
- High traction
- Can act as shocks for the robot when crossing defenses
-Doesn't allow you to be pushed in a direction perpendicular to your wheels
-Allows for simpler drivetrain
-You only have to power two sides of your drivetrain, so better motor
allocation with 3 motor gear boxes
-Can climb over obstacles (depending on drivetrain)
-Defending your tower is always an option if something fails
Mecanum:
-Can strafe
-Can be pushed in any direction
-Likely not enough traction to go up the ramps, and definitely not over the defenses like the moat and bumpy road.
- Less dependable, more to go wrong
-If you use 4 wheels, the most power you can give to each wheel would likely be a CIM and miniCIM, so not as fast as a robot that uses 6 CIM motors in its drivetrain
-Little to no use on defense, most robots can push you around
Your team can choose which ever it thinks is best for your strategy, but I highly recommend not using mecanum wheels. If you think its worth it, just compare it to other drive trains using a
decision matrix with objectives such as durability, multi-functionality, ease of build, and complexity.