So, I wanted to know does the Dawnguard strain of vampirism have all the regular perks of normal vampirism (sneak and illusion bonuses, etc.)? Nothing on the wiki explicitly confirms this. Can you become a Dawnguard vampire again and again (and maybe cure it with Rising at Dawn to become one again too)?

Also I just wanted to make sure that the Companions' quest line is now completable and you can still become a vampire? It always bothered me that when playing a vampire most of the time it made sense to join the College of Winterhold, however when presented with the Shalidor's Insights quest often it would want you to go deep into Ysgramor's Tomb - requiring you to complete the Companions' questline and previous to now cure you of vampirism and make it impossible to contract it again.

I thought I'd post it here as some of the answers may be a bit spoiler-y.

Serana is still the one turning you into a VL, regardless of which side you choose. No difference at all besides the vampiric artifacts you can only get siding with the Volkihar Vampires.

When the DLC comes out for pc the wikis will be loaded with info. For some reason XBOX users don't really contribute to wikias. Kind of bad but you get what you get

Maybe, but the xbox doesn't allow the same kind of testing you can do on PC, stats are almost impossible to know, the PC is where it's at when testing gameplay mechanics and getting precise information for wikis.

So no one has any idea? Someone could at least just look at the active effects they have outside the Vampire Lord form and answer my first question.

just don't tell serana to cure herself and you can get VL anytime you want, as for the werewolf aela only gives you one chance after becoming a wolfman