I've heard of it and heard reviews from other parents, but have not used it myself. The main feedback I heard from other parents was that it was fun & generally a good curriculum, but much too easy for gifted kids at the levels they suggested. For instance, the 2nd grade curriculum would be more appropriate for a gifted kindergartener or maybe 1st grader depending on how advanced the child was. I was told to order a higher grade level by at least one grade than your child is in. If you do wind up ordering any of their stuff, let us know what you think!