I cannot really judge without seeing the books themselves, since the original book is not publicly available without payment (who would have guessed), the start

I cannot really judge without seeing the books themselves, since the original book is not publicly available without payment (who would have guessed), the start up is still in beta and the publishers will surely overstate things. From the description, it just seems like the boundless version is inspired by the "paper" textbooks - but inspiration and copying ideas is the source of culture. But really, I would need to see both the books themselves and the boundless version to judge.