The iPad as a Writer Tool. Editing the first Daft

I am working on editing the first draft of my next novel, or novella if I decided to kill a part of it. I do this in the iPad, this allow me to read, edit, add and modify all the text I wish. The only problem with this approach is that if I want to know the exact changes is a two step process.
To my knowledge, there is no software in the iPad that allow you to track changes (plus I use text files), therefore if I made changes those are final. To work with this limitation, I made a copy of the ‘Original’ first draft and work with a second set of files, so if I want to visit a part I can, and it’s not impossible.
This allow me to work into the draft, edit, add, change delete and more without worry. If I need, I can always access the original text file using DropBox. If I have no internet, I can do it using my iPhone, as a second screen.
Editing in the iPad is fun, since you can get the full screen, you can also get the full reading experience that your reader will get, but you also get the ability to work into the file.
If everything goes as planned, this book should be revised in the next couple of weeks, and then shipped to the editor. We seem to aim to the end of may for this. Wish me luck.