Matt Gemmell is a professional writer, and has an interesting take on Ulysses as a long time Scrivener user.
It’s a difficult choice. For now, I’m keeping a watchful eye on the Updates pane of the App Store to see what happens with Scriv, but it’s Ulysses that’s on my iPad’s primary Home screen. The next book is being planned in there.
I absolutely love Ulysses myself, and was honestly expecting Matt to say something to the effect of "Ulysses is great, but Scrivener is just better for my type of writing. His take is absolutely worth reading, especially if you are debating which of these premium-priced writing apps to buy.