From a guitarists perspective.
If you are very much JUST STARTING, its a great way to start building finger dexterity and beginning to learn the neck of the guitar.
But
If you are an experienced player, not only does it not help you play any better, it hurts your playing ability. I realised that it limits to what your fingers can do and constrews what the feeling of what a real guitar does. Regardless, this game is really fun so just make sure you practice for about an hour after playing the game.
The ONLY thing I dont like about this game is that there is no option to download more games or expansion packs. The unlocking of other songs works well, but to be perfectly honest I've only heard of about 2 of those songs, being able to get more songs would definately be a plus, other than that, absolutely solid game.