I really like the Teaching Textbook series. One of the most widespread home school difficulties is that kids doing all their math at home can get frustrated and emotional; and when you are family working with family, emotions over math can mix in with family life. Any public school parent who has faced frustration with a math homework assignment (and I suspect that's most of them) can sympathize.
So the TT method, where the computer program teaches the course, can be very useful. It makes math assignments an objective reality, not some horrible thing a mean mother insisted be finished. This is kind of cheating, but I'll take it.
The program gives you a lecture, then practice problems, then a series of actual problems. After several of these, there is a quiz. The problems are graded in real time so that students don't keep making the same mistake over and over and imprinting on the neurons the wrong pathway. This also helps with the other stumbling block with home school -- at least it's a stumbling block for me -- grading. Life happens and it's often hard to get yesterday's assignment graded in time to do today's. With Teaching Textbooks, the assignments are graded as they are entered into the computer.
I do ask my kids to write out the answers in the textbook as well as enter them into the program.
There are a relatively few number of problems for each lesson. This can be a good or a bad thing. Also, it seems behind other programs (e.g. if your kid is moving from Math Mammoth 3rd grade to Teaching Textbooks for 4th, you might consider trying out year 5 instead). It's not a terribly rigorous program and the computer does have a few glitches, but it's a pretty cool product overall.