Base game
The base edition is the safer default if you only want the full game and do not care about cosmetic or starter item packs.
Editions and bonuses
Compare the base game, Digital Deluxe Edition, preorder bonus, and early purchase bonus before choosing a Final Fantasy Resonance edition.

Quick facts
The base edition is the safer default if you only want the full game and do not care about cosmetic or starter item packs.
The Steam page lists a Magitek and Grimoire Deluxe Pack with a chocobo appearance item, an exclusive character-related Limit Burst unlock item, and starter consumables.
Preorder and early purchase bonuses have conditions. The page should keep the deadline visible and avoid implying that late buyers receive the same items.
Steam lists the preorder pack as the Magitek Airship Passkey, Knight's Greatsword, Chestplate of Preparation, Magicite Shard, Tents, and Mist Potions. The early purchase pack is listed separately with Blessed Cuirass and Mist Ether.
Choose it only if the listed cosmetic and starter pack items matter to you. The base game is the lowest-cost option.
The Steam listing says preorder bonuses are only available to customers who preorder before release.