First, preview mode only works in the portrait orientation, so if, like me, you write in landscape and want to quickly preview the layout of your page, you have to physically turn the iPad into portrait to do so.
You can also utilize the Fountain formatting rules in a plain text document, then open the file in a Fountain-fueled editor for iOS, like Writing Kit for instance, or DubScript for Android, and let those apps handle the formatting for you.
Celtx also offers special buttons for element transitions, which you barely touch when working on a Bluetooth keyboard, and which saves your bacon on the onscreen version.
Check out the free, ad-supported version and see if it will do the job.
Polyamorous screenwriters need not apply. Fade In Mobile is also a universal application, meaning you can install it on your iPhone or iPod Touch as well. The price tag, while being a bit steep, allows you access to a lot of the fun tools mentioned but also helps you to stay organized and can be used to edit scripts from Final Draft.
I particularly like the placement of the element dropdown menu on the right of the keyboard, and a tab button on the left. Two downsides to this one.
No problem. Everything is industry standard and the format is easy with a simple toolbar. A serviceable way of working, but definitely not the most efficient.