[Hawiian Cadder]

There are too many varieties of both drive styles to really make a good comparison. Really when people ask this I think the main thing to discus is cantilevered vs non cantilevered wheels. When people say that supporting the axle on both sides makes the frame stronger I tend to disagree: Usualy the outer support is not attached by much (at least not near the middle wheel, where most of the weight is supported), and 80% of the weight of the robot is on the inner support. So unless your frame is really, really rigid, I don't think its any stronger to support a wheel on both sides. Cantilevered wheel systems are usually lighter, because there are only 2 wheel supporting members as opposed to 4. Because there isn't something in the way, the wheels can be moved farther apart, resulting in a more stable robot that turns with more force. The last and one of the best cases is ease of repair. A well laid out WCD can have all of the components removed without moving any of the axles. This makes repairs much faster, and require fewer tools. Every part can be replaced with nothing but needle nose pliers and an Alan wrench.