User blog comment:Sgt. S.S./Should I get Dawnguard or Dragonborn first?/@comment-4057437-20130414084630

Dawnguard allows two different play-throughs and two skill trees to complete, Dragonborn has only one storyline. That being said, the Black Books and the ability to reassign one's perks upon the completion of Dragonborn's main quest are big bonuses. (Dragon riding is like a newborn child, not much use, but Bethesda may fix/improve it.)