Well, only Amazon's is literally boss, but other retailers have stuff too.If you pre-order Final Fantasy XIII-2 from Amazon.com, you'll get the "Omega Boss Battle," an exclusive "coliseum battle" that adds Omega to your party after completion.
Best Buy is bundling a hardcover book with pre-orders, containing "Final Fantasy XIII -Episode i-," a novella connecting the stories of FFXIII and XIII-2. And GameStop offers ... a new costume for Serah! That last one is maybe a bit less impressive in comparison with the new playable content and the hardcover book. Final Fantasy XIII-2 will be released in North America on January 31.