Personally I envisage starting my projects off in Scrivener for OSX and then syncing to my iPad for working on the move. I’ve been using Scrivener since 2007 and don’t use a word-processor at all any more, except for checking my publishers’ copyedits. Why would you, when Scriv is a perfect writing environment all by itself?
At the moment I use Notebooks and Dropbox to sync my iPad with Scrivener, but it’s not perfect because you can only sync as plain text (and AFAIK it’s Mac-only).
I wouldn’t wait if I were you. There’s no guarantee the app will be out this year - though I very much hope it is, as I have a new project waiting in the wings. It would be so cool to have it in time for NaNoWriMo!
I am looking forward to an iOS version of Scrivener. I travel for my day job and would love to be able to use Scrivener on my iPad. Personally, I would love to have it replicate the program as much as possible since I would like to be able to work “normally” when traveling without having to spend time updating my home version with anything I write on the go. Saying that, I would love for it to be able to automatically sync between the versions using Dropbox and/or iCloud (though I have to date found Dropbox more reliable).
I’m recognize the enormity of the task, so even getting a scaled down version that has the binders, word processing capabilities, and some form of automatic syncing (without all the other bells and whistles in Scrivener) would be nice.