My 5 year old daughter and 17 month old son plays with it every day.
There are so many ways to use them (as toys, as learning material to teach alphabet, counting, etc). And I love how beautiful its pastel tone is! My daughter is asking me to buy more of this so that she can build more things. Highly recommend!
We have both mega packs of the rainbow and pastel and love adding more squares to our collection so my son can build taller structures.