My then DS6 used Time4Learning this summer. He LOVED it and I was very impressed by it. Although it did cost $20/month, it was definitely worth it because there were days when he would be on there for 4+ hours (and other days none, depending on our schedule). DS was not challenged at all in Kindergarten last year, but I retested him last month and he went up 1 to 2 grade levels in all areas of math. I'm guessing it is due to using Time4Learning for 2 months, because otherwise we had not worked on math.