Should I get DS (3) a Grimms rainbow?

[CatholicKidston]

Have I left it too late - is he too old to get the benefit now? Are they really all that brilliant? Will he play with it all day every day until he's 13 as people keep promising me? Or are they just a vanity project? I figure at the very least he can use it as ramps for his hot wheels

@Junobug Good That you mention the semi circles, was thinking about getting them but didn't really see how they fit in. I got the rainbow forest for Christmas, hoping he'll like to place the trees etc when he build his roads etc in the next year (he's 2 in Jan).