Ive tried dozens of text editors but Byword is hands down the easiest one to use, especially if you want to use it to work with Scrivener files.
Until Scrivener has an iPad app, the only way you can work with a Scrivener project on a mobile device today is to export the project as a set of text files and sync via Dropbox. Its not pretty.
But Byword not only handles that screwy workflow, but does it with aplomb, and makes taking Scrivener mobile possible.
Its great even if you dont want to work Scrivener too.
Rickzilla about Byword