read the title.

Vampires have way too many cons to them; the -100% regen is just not worth the rather minor bonuses. Werewolves are worth it only for the disease immunity.

which one should i become and what are the advantages and the disadvantages....

neither, stay human. vampires have no real redeeming feature for all the negatives. werewolves have disease immunity, and can feast on corpses to regain health, but their melee damage is pretty bad IMO.

The trick to playing a Werewolf is never actually turning into one

werewolvs have very little disadvantage, but their wolf form is sorta weak without using the it's shout (which can be spammed over and over and over)

If you are choosing one go Werewolf. Not because of fan love or any of that but because they run fast, they can tear through enemies, and are immune to diseases. I became one and I'm a happy camper where as when I would come down with Vampirism I would look at is like a plague since it had nothing useful about it.