It's been around for a while. I think you have to use their curriculum. It's accredited, I believe.
We used American School one year for Veronica. She was soooooo bored. We couldn't stand having to use someone else's curriculum the way they wanted us to use it. If I'm going to use a curriculum, I'm going to use it the way *I* want to. Plus, I don't like not knowing how she did on a test. It does a student no good to find out three weeks later what he or she missed. By that time they are on to something else.
That doesn't mean it's bad for other people. That's my opinion, and I know there are thousands and thousands of people who use American, Keystone, Citizens, etc., and love it.
We used one like it for Daniel, though they went out of business. At least he got an accredited diploma.