Song prices are beyond reasonable. The app itself is free. You get so much for the price it is insane. Even for the most expensive songs ($4.99) are fairly priced. As mentioned above, the transcriptions are dead accurate. You get a true score and one in tab. You get a mixer, with a click track, band track, isolated guitar track, and a track for you to record on. All tracks are mutable. BTW, this is assuming you bought the Guitar version of the song. You can loop, slow down (without changing the pitch, ) and work on just sections of the song. Also, as mention above the transcription moves along with the music. They have sales too. I just bought Montrose's Rock Candy for 99 cents. They have Paul Gilbert's Fuzz Universe, and Richie Kotzen Peace Signs and Paying Dues. It's hard to find Kotzen transcriptions. Those are mixed in with all sorts of a variety of artists. From Pop to Metal. They rate the difficulty of the song as well. If they had this 30 yrs ago, I probably wouldn't suck so bad today! LOL.
For the record, I was working on the Kotzen tunes last night. It was pretty nice to be able to see his stuff and then slow it down. I was working like that and pausing it. Today I will try and figure out the looping aspect of it.