My FLL team worked with a Robovation kit this summer, as the basis for a robotic "Avatar" project. Since we have received Vex kits to prepare for the FIRST Vex Challenge in Atlanta, we have compared them in detail, and just about every area is improved, some substantially.
The microcontroller is similar in capability, with 16 I/O ports and interrupt ports still present. Thesolenoid outputs have been removed, but the connection of up to two R/C receivers is allowed, each through a single cable (the Robovation controller uses up to eight cables for one receiver). The battery pack connector now accepts standard 7.2v NiCad battery packs without an adapter.
The R/C transmitter and receiver is included, a modified Futaba 6-channel digital system that seems very suitable to its purpose (and will drive 8 motors/servos, in a configuration where you slave two motors to each differential drivetrain). There is also a mode to use two transmitters with one receiver to control the chassis and manipulator(s) separately.
The "Erector-like" mild steel building components and the same, with a couple of new ones added. Delrin bearing have some new configurations, and axles are still square. 3 sizes of gears have been added, but the sprockets and chains have been removed (I understand they will be added back into the system in the Fall). The three motors are similar, with a better finish and a clutch added. A servo is also included (120 degree), in the same form factor as the motors. The wheels are MUCH better - no more soft foam that cannot bear weight without deforming. The hardware is still hex-driver oriented.
The programming system is absent, but should be available in the Fall. I understand it will be C based, with a Visual layer (on the idea of Mindstorms) available for simplified coding. Only limit switches and bumper switches made the beta kit, but as many as six new sensors should be available in the Fall.
All in all, my team loves them, and at half the price of the Robovation kit, with a very capable R/C system included, with many design upgrades, I feel that the Vex Robotic Development Systems are a great buy, and I look forward to our town group, the Sharon Youth Robotics Association (
http://syraweb.home.comcast.net/), sponsoring a number of Vex teams in addition to FLL teams in the Fall.
I have seen the Vex kits already in several Radio Shack stores, at least here in Massachusetts, so you should be able to get a look soon. Also, we have posted a Vex-oriented website at
http://eaglevex.home.comcast.net/, with lots of pictures, to chronicle our reponse to the FIRST Vex Challenge this Spring.