The Deluxe Doomwood Bow is an upgraded version of the Doomwood Bow. Like it says in the item description, it was reinforced to fire arrows at much faster speeds than the Doomwood Bow, resulting in more damage.
The bow can be spammed to stall in mid-air. This can also make a good weapon for sniping players due to the near silent sound of the player launching the arrow. If the arrow hits a player, mob or solid surface, then the arrow will lodge in place for 5 seconds before disappearing. Due to its improved damage, it is only available for players at level 100+.