We have always done Saxon until we hit Algebra. As Saxon progressed I was very frustrated that there were problems in the lessons we could not figure out the answers to. We had the answer in the key, but not how they got it.
Teaching Textbooks allows my son to do the problem, check it in the key, and if he doesn't understand it he can go to the DVD and it explains EVERY problem. This is a real plus.
We will continue using this curriculum through high school.