At the moment I am enthusiastic of the toy when my son. I build and then he throws everything. He also takes stones in his hand and looks at it. He himself does not build yet.
I think that toys are only really of interest to 18 years-month-olds and older.
I have noticed that the stones rub off on our tiles. The color can be easily removed from the floor while, but is still annoying and should not be, also because of Hochpreisigkeit this toy.