Don't get a set with a motor. Make your kids work for their fun. When they are using a crank, it seems like it would be cool to have a motor, but the motor coolness only lasts for a few minutes. During those few minutes, the kids can only watch the toy. They can set up a new pattern, and watch it. Then they get bored and walk away.
The motorized versions are good for store displays, but not for actually playing.