What is the incentive to playing as the dawnguard? I mean seriously

Huskies, awesome armor and anti vampire weapons. Enchanted crossbow bolts. Armored trolls. Awesome character diologue. Allowed to stay werewolf. Vampire hunting sidequests. Offensive restoration spells.

Etc.

Armored Trolls, Advanced Crossbows, Light magic among other things.

morality, not selling your soul to every daedric prince that looks your way (I know, already an issue in vanilla, but dawnguard adds another way to get into soul debt, as I believe vamps belong to molag bal, so vamp lords would be moreso?)