Meet the Makeblock mBot Mega Robot: a Raspberry Pi coding kit that teaches your kids Scratch and Python programming. It comes with 4WD mecanum wheels and works with the Makeblock app. This robot is based on Mega AT2560 and lets you connect up to 10 servos, 8 DC motors or 4 stepper motors.
This programmable robot works with Arduino IDE. It has a metal shell, so it will last you for a while. The mBot Mega is compatible with iOS and Android devices.