I used the app a while ago along with the website. I loved the app but found it did not keep progress on both if I did stuff in one and not the other. Also I found the practice sections did not update either and I believe some tutorials were no on the app but on the website. As I have not used it for a while can you tell me if this has changed at all?
I am interested in signing up for the app but had the same question as you.
The original and primary purpose of the App was to provide the means to play along to songs as an aid and support to learning.
The App is produced by Musopia, an independent company, in partnership with Justin but is not an integrated part of the JustinGuitar website.
The lessons for Grade 1 and 2 were added to the App to increase it’s value and provide some convenience. But I always encourage members to use the website lessons as well, since there is additional learning material.
Of course many people learn successfully just using the App, at least to reach the level of ability achieved through Grade 1 & 2. Thereafter if they wish to continue then they switch to the website for Grade 3 and more.
Beginning to play songs using the App is an effective way to develop timing and rhythm. But many people also feedback that when it came to learning to play songs from memory, as is part of the recommended criteria for completion of Grade 1, they found the karaoke style of the App made that harder.
Hope that helps and please do ask further questions.