I have a niece of 7 and a nephew of 3 and 3 neighbours children of 3, 5 and 6 and they all absolutely adore this paint!
It does dry an awful lot quicker than regular paint, although you still need to roll up sleeves and suchlike as it can initially get on clothes, and once they get the hang of the brushes can create some fantastic rainbow effects.
However, with the 3 year olds I have found that a little extra help is needed so that the big pad brush is not wiped over all the colours getting a rather muddy colour result..they just needed to practise wiping the pads straight up and down rather than side to side..although some amazing colour variations have resulted with only short sideways mistakes..it's all learning after all.
Hand painting can also work quite well if the older children are fast at putting the paint on their hands and then onto the paper...the mess on hands and fingers is something to behold!!
I gave this quite a good result for educational as for the older children it was a perfect way to show how mixing your colours you end up with different ones, my niece loves trying to make as many shades as she can!
Overall, highly recommended and my tip of the day is to buy a roll of lining paper (wallpapering stuff) as it is nice and cheap, large quantities and nice and wide sizes too!
Enjoy!