Not recommended
This app. misses the mark. The M4A file is created on the home computer and is no more adjustable on the gig/classroom than an MP3 tune in iTunes. This is basically a front end MP3 player that plays files you create on your home computer. You can't even change the # of choruses on the phone.
Add to this the fact that it only works with Windows!Crapola!
Lame. You need to take a look at realbook. I didn't see that you have to have biab 2011 or this app is useless. My older version doesn't work, so I wasted .99 cents. All that server crap in your app is crap. Basically I can make mp3's and play them in iTunes and that is about what this software does. Put a little thought into your software to let people make songs on their iPhone, save, and playback. No server bs! Please update quickly before everyone finds out how lame it is!