Reading through my copy, the special edition Fourth Wing seems tailored for the fantasy collector crowd rather than casual readers. The sprayed edges are a nice touch – black with a red dragon-scale pattern that feels suitably thematic. Inside, there's a map of the Basgiath War College, which honestly should be in every edition given how much time we spend navigating those halls.
A bonus chapter from Xaden's point of view is the real draw. It covers a pivotal scene from late in the book, and getting inside his head does clarify some of his more frustratingly cryptic motivations. It doesn't radically change the story, but it adds texture. There's also some author commentary on world-building, which I skimmed – it felt a bit like DVD extras for a book.
The overall presentation is solid, with sturdier binding and cover art. Whether it's worth the extra cost depends entirely on how deep your fandom runs. For me, the Xaden chapter was the only truly exclusive element that enhanced the base experience.