This is really an awesome app. It is well thought out, well designed, clean, and workflow friendly. One of the coolest aspects of SongbookPro is that it creates, in real time, an HTTP web client on your desktop using a TCP/UDP port. Most editing can be done on your desktop and it automatically communicates with the iPad app. No software is required on your desktop computer other than a browser. Very well done.
Additionally, SongbookPro contains a very accurate parsing engine for Microsoft Word documents. which was important to me seeing as how I have hundreds of them. The documents are parsed to ChordPro and require minimal editing in the (Best in class in my opinion) ChordPro editing widget. Essentially, chords that were entered manually on the line above the lyrics in Microsoft Word were very accurately positioned when the word document was parsed into ChordPro.
SongbookPro has basic MIDI support. I did communicate with the developer who says that more MIDI support is on the way. I am able to send a program change to my beat buddy upon opening the song. I'd like to send a tempo change as well another PC to my Voicelive at that point too, but have not figured out how to do it.
In summary, this is an absolutely awesome app. The ChordPro editor alone is worth the price of admission.