[Kyle Love]

Mecanum wheels take immense amounts of tweaking of the rollers, just a half turn of the bolt too much can make it not spin freely. There also needs to be some kind of suspension, spring steel makes a really good suspension for mecanums.

From the construction stand point. If you haven't built a mecanum in the fall, it may be a little too labor/software/testing intensive to be successfully done in the build season.