I have had a powerball for about 3 weeks and can get around 10.5k, so i'm not a complete noob.
I got my Foot Trainer delivered yesterday despite the other bad reviews- i though "It can't be that bad".
Its basically unusable. It took me hours to get to the point where i could keep it spinning for more than a couple of seconds. Starting isnt a problem if you really go for it in your hand and give yourself time to get it into the cradle before it stops. Its incredibly awkward to keep it going and potentially dangerous for your Powerball- the strap worked its way off my foot and my ball was sent flying into the wall. Not impressed.
I tried running it in my hand in the cradle for a while, and as soon as you get above 7 or 8k, the lid flys off, so its not even strong enough for normal use.