User blog comment:Thewikilover/Dawnguard or Vampire? Which side has more benefits?/@comment-1726879-20120714085750

Basically it runs down to whether you are heavily dependant on Vampire Lord or not. If you have little care for it, then the only point of joining the Volkihar is that you can turn your spouse into a vampire, other than that, the dawnguard have a (debatably) better home, you gain followers by joining them, you have easy access to all forms of Dawnguard armor (which is better overall compared to vampire armor) and weapons, access to armored trolls, and you don't have to run around a castle filled with blood trails and living corpses sat on tables.

Personally, I believe that Vampire lord is too much of an inconvenience to be useful, and issues due to their size may force you out of it in certain dungeons. If you can handle that, and prefer it to followers and weapons, then go for Volkihar.