What is it
I tried Rough Draft for a small writing, and it's a interesting text editor. I can see how it's attractive to some people. It's try to make the first draft writing more solid by mimic paper writing, all deletes are strike throughs rather than normal delete. That requires more focus on first draft, and possiblly the first draft would be more readalbe than normal.
Not for me
I do feel it's a great try and would be fitful for a lot of people, unfortunately it's not for me. It doesn't fit in my writing process. If I'm writing a long essay, I usually write directly in Ulysses, for a short piece, I write in iA Writer. After I write anything, I rethink about the topic and try to argue with myself, if I find something that not solid in the writing, it would end up rewrite some of the writing. Fishing the rethink, I would also check my language, since I'm not a native speaker, and usually I use iA Writer to do this step with its focus mode function. That's very helpful for me. I would say it's still worth a try for most people, and probablly end up useful for a lot of people. You should try it for free in the Mac App Store