This is the only app I've found that offers synthetic phonics, as taught in UK primary schools which means it deserves a good rating for that alone! Other 'phonics' apps have nothing to do with real synthetic phonics, and just follow the alphabet. For example, they do not teach the sounds that are created by two written letters (sh, ch, th, oa, ee, oo er, etc...). This app does teach this, which is great. Also, the spoken sounds are the correct units of sounds (/s/ not /suh/, /m/ not /muh/) which is rarely done on these apps.
I have only given 3 stars for two reasons:
1. It would be good to have a little variety in the games - they are all matching memory games, so it's not too versatile, and children will get bored quickly. Perhaps a couple of other options, eg. bingo, listen and spell, match the word to the picture - all standard teaching tools.
2. The bigger reason - the speaker of the sounds is not a native English speaker. She has a very good accent, but it's not perfect (her pronunciation of 'tie' and 'pig' do sound quite foreign, whereas other sound she does very well). Given the nature of the app (teaching units of sound) correct pronunciation is vital. A British speaker (and an option for a US speaker for American users) would be essential if this app is to hope to have any long term success.