In reply to ACollins:
We got one last year. Within an hour or so I was balancing and walking a few steps. But if I left it more than a few days before doing it then I was more or less back to square one. I've not done it now since the autumn, so I expect to be more or less beginner level again.
However, for me it's some entertainment to play on while hanging around at the park or having a bbq, so not too bothered if I never get that good at it