On the plus side there are lots of parts, all of decent quality. Putting it together is fun and will give you lots of soldering practice. The instructions are minimal, but adequate for assembling the thing. The instructions are completely lacking when it comes to running the thing however, which leads us to the minuses.
It doesn't really work very well. There is no micro-controller chip, just a simple comparator providing 'bang-bang' control. This makes the circuit easy to understand, but makes the robot lurch around badly. My son was extremely disappointed with its crappy performance - but he did enjoy the build.