Is this to be used as your reading program, or as supplemental materials? If you are allowed to “pick and chose” the books as you need desire, then I think they could be a good resource. You could match books to readers and use the parts of the lesson plans that work for your students.
Or, I believe it’s true, that you can search on A to Z for specific lessons that you could match up to strategies you know your students need.

My school also just purchased the A to Z license with the idea that we can print the books and send them home. Many of our students don’t have access to any books at home. My worry is that it takes the challenge of picking your own book and learning from your own self selected text if I assign books to be read at home. I also have many of my higher students that HATE the books and refuse to read them. I see these books being a great resource for beginning readers but not as useful as the students progress in their reading ability. Any thoughts?

I started using the A to Z books this year to supplement my classroom library. Unfortunately, our school does not have a book room. Their fictional stories are lacking in many ways, but I found their non-fiction to be pretty good. I do appreciate their extensive book list for each level and it is a great resource for my low readers. Our school mainly uses the Wonders reading program which only offers one leveled reader a week and we do not allow these books into their book boxes. A-Z does try to align some of their stories with Wonders, but you have to know the Wonders program really well in order to pick up on the A-Z stories that match. I think using them as another resource is the way to go. You know your students the best and giving them variety, in my opinion, can boost their interest in reading.