Best toy ever!
This is what my nephew said while engaging his older brother in building "the next thing." I bought this toy for my nephew for Christmas this year. My nephews are 7 and 9 years old, and they love to build.
According to my sister (their mom), this toy has gotten hours of use in both creativity, and cooperative play. They build things, challenge each other, and "invent" things. I got this set along with a similar set that comes with balls for rolling in the ramps and contraptions they build.
When my sons were this age, they had similar sets, and loved them.