The skill and grade level progress has been well worth it. Each of my kids have worked up to an hour a day regularly on the math. But the progress is satisfying. We are going to take a few months off as soon as we get done with these grade levels. This has been great for my son who prefers to type on the computer rather than write with a pencil.
Some parents choose very little review and move through the course VERY quickly.
Which is great for starting the child below or at grade level and then later slowing down and being more thorough as the child hits their skill ability level.