Mini Micro Vs iScoot
If you think about how you would feel riding a scooter, the handlebars would be comfortable around waist height. This is the same for your child. There is only 3cm difference in the lowest handlebar heights between the iScoot and the mini micro but obviously the lower option is going to be slightly better for children on the small side.
Lean and Steer Turning
Although the mini micro isn't foldable, the handlebar can be removed from the base so it can be easily stored or taken on holiday quite easily in the boot of the car if you wanted to.
Summary - Mini Micro
The mini micro has been designed very much with the age bracket of 3 to 5 year olds in mind. Everything has been considered on this scooter to make it as lightweight as possible. This is because a lighter scooter is much easier for children in this age range to manage and control.
This is in part reason why the mini micro doesn't have a height adjustable handlebar or a folding mechanism. All these extras will add weight to the scooter and ultimately make it harder for little ones to use.
Despite being lightweight every part of this scooter is also well designed and well made to withstand the play of a young child. For example, the deck is made of flexible fibreglass and has been reinforced. It's therefore brilliant at absorbing shocks from bumps from the pavement.
Summary - iSCOOT
The iscoot has a different aim in it's design than the mini micro. It is very much designed for the growing child from aged 3 and well beyond that (up to 8 or 9 years).
It's not as lightweight as the mini micro but as kids get older, bigger and stronger the weight of a scooter is not very important as they will have the strength and ability to manage something heavier.
This is why the iscoot can afford to include a folding mechanism and a heigh adjustable handlebar as it accommodates is a much wider age range. These factors are more important for a growing child than something that is light.
It is also cheaper which may affect your decision as to what option to buy.