I bought a new iPad Air last month, and this is pretty much my first exposure to this type of device. I compose music in a more traditional fashion, using musical notation rather than a piano roll or whatever. I've begun checking out what is available for the iPad, and it quickly becomes obvious that most of the products at iTunes are pedagogical in nature. Of those that aren't, only a few have free demo versions, and of those few, I can't say I care much for any of them.
I have compiled a list of the notation-based apps at iTunes. It would be great, if you are familiar with any of the apps I have listed, that you would take the time to comment on it or them. It would certainly be a big help to me. Reading their descriptions is useful, but the descriptions usually don't get into descriptions of the interface and intuitiveness. To me, these are the most critical aspects of any piece of software, but they are usually the aspects that are ignored in descriptions. None of the following apps are very expensive, but if I have to do a trial and error to find one I like, the costs can start adding up, and I will have likely wasted money on apps I'll never use. I don't like wasting money. Here's what I've found over there so far in more or less the order of discovery:
iWriteMusic by the iWriteMusic Project. This one came with a free version, which I didn't care for.
Finale Songbook by Make Music, Inc. I'm pretty sure you have to have a copy of Finale to make full use of this "songbook". I don't have a copy of Finale.
Symphonix Evolution by Vinclare. Has a "player" for $0.99.
Reflow Score Writer by Gargant Studios
Guido Creator by Killian IT Consulting
Symphony by Xenon Labs LLC
Notion by Notion Music Inc.
Guitar Pro by Arobas Music
Scorecerer by Deskew Technologies. This one has a free version.
Being a guitarist, I listed Guitar Pro because I've found that sometimes notation based software can't display the music the way I'm used to seeing it. But it is probably going to be limited for other uses. However, since the price is affordable, I'll most likely add it to whatever I end up with, just so I can score guitar music accurately.
To me, Notion, Symphony, Symphonix Evolution, and possibly Scorecerer appear to be contenders for what I need. Any input you'd care to provide regarding the above or different applications will be most appreciated.