Well, quite honestly, this program did not fit well into our family so it was difficult to find time to try it and give it a fair review. We are Charlotte Mason style homeschoolers who love the flow of our day, and it was a bit time consuming to hunt and peck through the lessons to find ones that would support our current lessons for that specific day. We are also Christian homeschoolers and we prefer a core curriculum that centralizes on Christ and the Bible. This curriculum does not do that, of course.
It would fit well into a family who wants a secular core for their education and where the parents are short on time (pregnancy bed rest, many doctors appointments, travel, dual income earners, etc.). I don't find that it would work well as a supplement across the board with all curricula, unless one is following a public school curriculum at home, such as K-12, and since K-12 is on the computer and paid for by taxes in most states, I don't really see the point. For a family that likes to follow rabbit trails or do lots of unit studies, this could be used as a core so that the basics are covered and gaps are filled in... and I think that is this curriculum's best use... a core that one might add to and supplement with other things, than as a supplement itself.
One thing that bothered me every time we logged in, is that there are too many steps to switch from one child to another. I prefer other programs like IXL.com or ReadingEggs. com where one signs in once to a family account and the kids can easily click on their own icon and enter a small password. If you have a long last name, and a larger family, as we do, it's a real pain to fill in first name, last name, and password with each change of student, especially the younger ones who may not know how to spell everything yet. Many parents might want to use this program to keep the preschool/kindergarten/early reading set busy while they work with older ones, and with such a long sign in process that needs mom's help, it kind of defeats that purpose.
All in all it is entertaining way of learning for the kids, and I think we may try it a few more months to give it a fair shake.