Full ABC was by far my favourite app; it showed each capital- and lower-case letter and several corresponding words, pronouncing them clearly (and starting first by giving the starting letter sound). It didnt give any annoying prompts and just had some low-key, soothing music and nature sounds in the background -- nothing youd want to turn off after your child left it running for a couple of minutes! ABC Tracing and Number Tracing, I might be too much of a Montessori purist to fully love, but Miss G enjoyed them and has requested them several times. My issues with the app are that it refers to letters by their names and doesnt seem to have an option to refer to letters by their phonetic sounds -- as they should in Montessori; and, the "star" rewards that children receive after they finish tracing each letter. Of course, there cant really be much sensory feedback on an iPhone screen but there is a tracing "sound" like pencil on paper that gives some sensory feedback, but the sound doesnt change as the finger strays from the letter shape. The number app was my preference of the two. (The benefit of tracing the letter is allowing children to develop muscle memory, so this is a much better app than something that just "flashes" the letters at the children and doesnt encourage the tracing.) I think the apps are a great option for something entertaining but not overstimulating on car trips or during busy appointments.