User blog comment:Agent of Dibella/DLC/@comment-5450493-20140102184832

Dawnguard is my personal favorite. It has a great questline and expands on Skyrim's already sizable explorable terrain. The two castles and the new characters are also amazing. The thing I liked about Dawnguard was that it was in Skyrim and I felt more connected and involved  because of that.

On the other hand, Dragonborn has more "stuff" with it. It has a pretty good main questline, but it has an entire world's worth of places to explore, bad guys to kill and a load of new factions and things to do, not to mention beautiful new armor, weapons, and the Black Books. If you're a collector and an explorer, definetly go with this one.

So Dawnguard has the better main questline and characters but for the sheer amount of content, interesting side quests, new locations, and cool items, Dragonborn is the way to go.