[IceStorm]

I would say to go for it. Nice thing about mechanum is that if you run into problems you can always just switch them out for standard wheels of the same diameter and run that way. No need to make major mechanical changes.

Biggest thing I would say is to get your drivetrain built early and into the hands of the students. Driving practice is going to be more important than anything else if you want them to use it as anything more than a tank drive robot. We have ran mechanum for a few years now and the new kids tend to forget about the strafe and rotation abilities until after they have had a lot of practice with it.