It's a trade-off between features/usability and price. I'm sure this one has its niche. It's much cheaper than a Lego Mindstorms kit, and probably easier for kids to use since they have the android and ipad interfaces.

But there is an ultra low cost (~$10) robot kit in the works (trade-off of course being less features/usability), but it's not available yet: https://sites.google.com/site/affordableeducationrobot/home

At $99 is the Pi-Bot http://pi-bot.org/

$50 Hack-E-Bot http://www.hack-e-bot.com/

$100-$150 littleBits http://littlebits.cc/

$99-$250 Finch & Hummingbird http://www.birdbraintechnologies.com/

$250 Arduino Robot http://arduino.cc/en/Main/Robot

$100-$150 Parrot Minidrones http://www.parrot.com/usa/products/minidrones/

and many others