We use Reading A to Z and raz-kids. It is a great way to differentiate. We use reading a-z and pair it with our basal series. Raz-kids is great on the ipads. I always check on the website to see how the kids are doing. They really like to see how many books they have read and know when they have gone up a level. They also like to record their readings. I am able to listen to them after school.