That's a toss up really. I'm having a ridiculously big time with RE6, but I own Dragons Dogma and love it too. It boils down to if you want a massive open world in a fantasy setting, or just some good old fashioned shooting zombies.
Sandbox Zombie game with RPG elements and heavy character customization and equipment farming set in modern day. My ideal game.
DD has some really good combat and a nice tense of exploration and one of the best boss battles this generation. However most other aspects of it are pretty dull. the world isnt interesting, the enemies will wear thin after a dozen hours and they respawn, story takes forever to get going, 90% of the quests are boring generic fair and theres no interesting characters. its a fun game, but imo its only worth about $20. Lot of content and some interesting online mechanics though.
RE6 also has good combat, a better sense of atmosphere and art design, enemies objectives ect. are all more varied. It takes a bit more effort to get used to its mechanics and its a bit inconsistent with its design. It also has interesting online modes and unlockables and a nice amount of content. A bigger emphasis on story and characters as well. Personally id say RE6 is more worth its acking price even with its faults.