I just reviewed The Factor Tree for The Bzzagent.
While I think it would be great for a child needing some extra practice after school, it is not meant to be the teacher.
As a teacher, I think it lacks a lot of “teaching”. Reviewing, yes, teaching, no.
It works well, and it was very easy to sign up. I just can not recommend it for homeschoolers.
Using the beta test to find out where your child is in their learning, is a good tool as well. I was able to see that I needed to back up with my son and reteach double digit math. But, this program does not teach, it just give the problem, your child answers them, and then if they did well, they get a medal of sorts. Which I think is great!
If you have a child in a traditional school, I think this program will fit your needs. It give the problem and your child answers them. Does it teach? No, but does it “redo” what is already taught? Yes.
I do give it thumbs up, I just would not recommend it to homeschoolers.