We used the books. I've heard that the books aren't published anymore though, so online might be the best option now. We can still find the books at our local homeschool bookstore, and you can also find them at Amazon through resellers. I personally like the books because you can take them with you when you're driving kids around to lessons etc - where wifi isn't always available.
I've also heard some feedback that the books are a bit more rigorous and better for long-term retention than going through it online. I personally haven't seen the online version, so I don't have any input on that.
polarbear
