Mecanum wheel robots are fun as they can change direction fast. This Mecanum Wheel Robot Kit comes with everything you need to build your own. It is based on Makeblock hardware. It comes with encoder motor driver, wheels, anodized aluminum base, and an Orion microcontroller.
The main controller is Arduino UNO compatible. The robot has a speed of 1 m/s and max load capacity of 40kg (depending on the size).