So, I have some songs arranged using Guitar Pro on my Mac. I drop them in a shared Dropbox folder to share them with my bandmates. I can then use the Dropbox app on my iPad to load them into the Guitar Pro iPad app.
The Guitar Pro app is great for learning and practicing. Besides showing notation, it’ll play the song plus the parts for other instruments. In my case, all the songs have guitar, bass, and drums. I can mute individual instruments. So I can have it play the guitar part—alone or with the other instruments—when learning the song. Then I can turn the guitar part off and just play with the bass and drum tracks while practicing. It can also adjust the tempo, so I can slow things down until I get the parts under my fingers.
The trouble with Guitar Pro, though, is that if you have a guitar amp/effects app—like AmpKit, AmpliTube, GarageBand, JamUp, &c.†—running in the background, Guitar Pro kills it when it starts playing.
Another app—TabToolkit, which was around before the Guitar Pro app—doesn’t suffer this problem. It can read Guitar Pro files too. TabToolkit doesn’t sound as good as the Guitar Pro app, though. At least, to my ears.
To practice with the Guitar Pro app, I instead have to use my Vox amPlug, Digitech RP-350 multi-effects pedal, or one of my Crate GTD15R amps. All of these have an “aux in”. Just connect the iPad headphone jack to that. Not as convenient and portable as just guitar, Apogee Jam, and iPad; but it works.
The same situation exists with iReal b and Chordbot. These are “band in a box” style apps where you enter a chord progression and it generates accompaniment for you. The iReal b app will kill a guitar effects app running in the background, but Chordbot won’t.
†In all of these apps, there’s a “run in background” option that you have to turn on for them to stay running when you switch to another app.