A comparison I typed up 7 years ago that seems to have helped a few people choose between Dawnguard vs Volkihar.

Dawnguard gets:

• Pet huskies
• Pet armoured trolls
• Master Level trainers in Archery, Heavy Armor, Restoration, and Smithing.
• A couple followers
• Better crossbows
• Easier access to Dwarven and Elemental bolts
• Easier access to the spells Stendarr's Aura and Vampire's Bane
• Chance to convince Serana to cure her vampirism.
• Attacked by Volkihar Vampires. (I think) Guards/Citizens will get involved with the fight, risking their own lives to help.

Volkihar gets:

• Pet death hounds
• Master Two-Handed trainer and Expert speech trainer
• Thralls in the castle you can feed on
• The Ring of the Erudite, Ring of The Beast, Amulet of The Gargoyle, and Amulet of Bats
• The Bloodstone Chalice, to enhance your vampiric powers
• A free player home with merchants (the castle itself)
• The chance to turn your spouse into a vampire
• Easier access to Necromantic Healing and Heal Undead
• Attacked by the Danguard in the wild. Guards/citizens won't help with the fight.

Both sides get:

• Serana as a follower
• Auriel's Bow and Bloodcursed arrows
• Access to Vampire Lord form and Bloodcursed Arrows*
• Durnehviir
• Radiant quests to kill vampires**

• As long as Serana is still a vampire ** Yes, Members of Clan Volkihar will request that you go kill vampires. Don't think the Dawnguard are the only ones upset at random vampires attacking towns!

How do you choose to play the game? Do you enjoy questing, or prefer seeing the world and messing around? Do you consider yourself a roleplayer, or are you more "serious" about the game? How vanilla do you like your game? Fresh as a new download, a little bit of QoL, or total overhaul? Cheese or no cheese?