This app is quite complete in terms of information and might be useful when starting the game. But main feature, the skill tree planner, is not working yet and had been "coming soon" for the past 6 month.
So with little hopes that this feature will be developed one day, I would say that this app doesnt worth the money as you can already find all of this content online for free.
However I have to admit that I have not used he interactive map as I did not want to spoil the pleasure of discovering new places in Skyrim, so my grade doesn t include this feature.
Georges jungle about IGN App For Elder Scrolls V: Skyrim, v1.2