Today is The Mark's official paperback release day! Personally, I always prefer paperbacks - easier to carry around (nope, still haven't converted to an e-reader) - plus this one has the snazzy new cover that matches The Vision:
As opposed to the Snazzy Old Cover that's on the hardcover version:
Or the Snazzy Really Old Cover that was on the original ARC, but got scrapped when another book used the same stock photo:
Anyhow, The Mark in paperback is available in all the usual places, including through the links you'll find here.