SO. MUCH. FUN.
We brought them to Houston this summer and had an absolute blast playing around with it in the hotel pool.
It's simple to use, just push the buttons on the handles and the propellers start. Steering is done by angling the fins up or down. And it's FAST. Really really fast. You notice it most when you stop, one second you're cruising through the water like James Bond, then you let go of the power buttons and you're stopped, just like that.
The battery charge lasts 30 minutes so a long time in the pool, and the charger is nice and beefy. The whole thing comes in a bag and it fits in a carry on :D
For under $700, it's one of the most affordable pieces of mainstream and adaptive use equipment I've found.