I bought this for my daughters 11th birthday. She is very into rollercoasters and how thay work and this was the perfect gift for her. It took quite a long time to set up and is easy to take over as an adult, but it was worthwhile. Once the tower was built all the family got involved in the suspension adjustments (and chasing after falling marbles!) to make it work and the satisfaction of getting it to run was immense. My daughters friend now spends hours with her trying to make all sorts of different shape tracks and without realising it they are learning physics and having a great time.
One thing to note is that you need a lot of room for this, especially when kids become creative.
Another thing is that after spending hours making the initial tower alot of the essential clips that hold the suspension strings broke on assembley and are still held together by sellotape. As there were no more in stock at that time and my daughter would rather keep a broken one than sending back the one she had already made - we are still chasing some spare parts.
Overall a great product if it wasn't for the boken clips (and they are pretty essential) and definately not just a toy for boys !