The VexIQ robot system seems to have several advantages over the Lego Mindstorm.
1) Price: VexIQ super kit is only $299.99 and contains the following:
The Super Kit is an all-encompassing introduction to STEM and robotics. Students can use the familiar handheld Controller to drive robots right out of the box or program them to run autonomously using the additional Smart Sensors. While the included Clawbot IQ instructions help students easily build their first robot, the intuitive snap-together parts mean the sky is the limit for their VEX IQ creations.
- Over 850 Structural & Motion Components
- 4 Smart Motors, 7 Sensors, Robot Brain, Controller & Batteries Included
- Storage Bin & Tray included for organized storage of all parts
The Lego Mindstorm kit is about the same price, but limits you to 4 sensors and 4 motors. The VexIQ will let you hookup 12 of either. Also, there are a lot more gears and drive chain options that will allow for a wide variety of robots to be built: