How I Use It
We subscribed to AR in order to replace reading logs to track home reading by students. What we have found over two years' use is that the same students who did not fill out reading logs also don't tend to log in to AR and take the quizzes. It isn't engaging enough to maintain their interest and keep them coming back. There is a teacher-driven rewards system that AR has designed, but without external incentivization the program hasn't met our goal of tracking home reading. (We know kids who are reading lots of books, but not doing AR because it's seen as a chore.)
AR does have almost any published book in their database, and kids like finding books they've read. However the comprehension questions tend to be very detail-oriented, not higher-order. If a student doesn't take the quiz within a day or two of finishing the book, they may do poorly because details like "what fell out of the bag when Suzie tripped" might be lost even if they did get the bigger ideas in the book.
AR provides free trainings on a yearly basis. These are very helpful to know and use all of the features in the program.
Unless a teacher is willing to incorporate this into their daily routine and give it ongoing energy, it probably will not amount to great results for you. Also you need to be sensitive to the kind of reader your students are. Not all kids will remember the details of stories, even if they understood and liked the book, so not all students will succeed on the quizzes.