I got the beginner set with my daughters in mind. I knit and crochet, and my girls crochet, the the 2 needles in knitting seems to stymie them.
I know my 11- and 9 year-old will be able to pick this up quickly. I think it might take the 7 year old a little longer because going through the loops with only the string holding them open takes a bit of dexterity.
The videos were a great help. I love that it is included - you don't have to buy a class to get the visual instruction. For those who know how to crochet, you have to slow down and pay attention, because it is different.
I think this is a great product for those who want to knit but just can't get the hang of it. My girls are going to love it!