[DampRobot]

If you want to build something you'll use in the season, build a WCD. If you want a cool drivetrain that you shouldn't use for the season, build a mecanum drive.

For a myriad of reasons, WCDs are great drives for the season. Their maintainability and reliability are second to none, they drive very well, and are easy to machine compared with other "top notch" drives like butterfly or swerve. They're also very easy to learn to drive, especially with a drive system like cheesy drive, yet have a very high upper end in terms of performance. Butterfly, swerve, and to a large degree mecanum are comparatively hard to learn to drive in a short amount of time. Plus, building a drive very similar to the Poofs or the Greybots does have some innate cool factor.

Mecanum is very cool though. Non FRC people love omnidirectional motion, and the ways those wheels spin can look very cool too. It's a also less difficult to build than, say, swerve, although probably harder than a WCD. Buy some AM components and design a chassis to hold it all together, and you're most of the way there. However, I would not encourage you to use them in the season. While their lack of skills on defense is probably overrated by most people, they have other disadvantages too. It's a quite heavy system and usually forces you to have a higher CG by necessitating bigger wheels. Also, it's basically never driven to its full potential in a match. Unless drivers get a ton of practice beforehand, they never are able to take full advantage of its strafing abilities.

Don't build a swerve. Unless you are really really on top of your game, the project will be a failure, most likely because it will never get off the ground. Even of it does, lots of things can doom a swerve drive, most prominently poor control. Designing a swerve drive is a great challenge on the other hand. I've done it, and it's very rewarding.

Good luck this offseason! Your work now will definitely pay off come 2014.