For now I only see positives:
I was delivered in less than a week, as the product is an import.
I mounted easily in 10 minutes alone, despite the instructions in English.
It seems particularly strong: the scooter is made of iron, not plastic.
The rear wheels are close enough that my son does not butt in with his free foot pushing.
The board is not too high: the point of low gravity makes the scooter very stable for children.
The 4 wheels make it as very stable: My 20 month old son was launched in minutes!
The board has a non-slip grip.
It is scalable: it can be from 4 to 3 and then 2 wheels.
It is foldable.
The handlebar is adjustable according to the size of the child.
I must say I'm really blown away by the quality of this product, the price is more reasonable.