I used them both, and I like Glencoe better, because it shows step by step instructions, and on the side panel, it describes what they were doing, and they also give examples applying the concepts, and also, these examples are relevant to the homework, so by looking at them, it helps students answer their questions.

I’d like to point out that most atheists haven’t read ‘On the Origin of Species’ either. I’m an atheist but I had to mention that. The book shouldn’t be treated as a bible for atheists. It’s not about God and his role in the creation of the world (or lack there of). It’s a scientific publication that Darwin wrote to publish his findings in the natural world and to put forth a scientific theory (natural selection/evolution) to account for these observations. Conclusions can be drawn from the results put forth in the book, but that is not it’s central premise. Have you actually read the book?