I’ve been buying other robot kits to experiment with - one with car-like steerable front using a servo and single drive motor, another with solid plastic wheels and a grid system for prototyping on. Both are also based on Arduino, and both being considered for upgrades or alternatives with the Explorer 1 kit system.
I’ve bought a grid board to tinker with too - where I can mount various components, and a bluetooth master module - so I can have one robot drive others and perhaps make flocking behaviour.
This means I also have a few days of robot building to do too.
Meanwhile - I am waiting for new stock to arrive as we’ve sold out this week! It is already in transit- and all the kits will be back on soon!