I have just bought this scooter for my six year old daughter, it is the second one of these i have purchased. I bought one two years ago for my then 8 year old son. As soon as my daughter was old enough, she had to have one as the riding experience is unique and is alot of fun.
It is unlike a regular scooter in that the back wheel is on a caster and so it spins up to 360 degrees, like a skateboard wheel. It offers more movement and freedom to a regular scooter, however, without some of the obvious dangers of a skateboard.
The scooter is very simple to use and adjust and extremely high quality. After two and a half years, my son's scooter has very little sigh of wear and tear and no rust.
Highly recommend for 6-7 year olds and upwards. I would suggest knee-pads just to begin with until the child is used to the different movement it offers