Ok so, after playing around with the two most popular vampire mods for F4, Khajiit feels he can now post his opinions. Now this will only cover the basic gameplay changes; this one will not be getting into too much detail with some of the features of Nuka Sanguinare (Khajiit has not gotten far enough to test some of the settlement features of that mod).
Nuka Sanguinare-
Pros: Feeding on the living (bound to the ‘R’ key on the menu while the cursor is on a person), vampire abilities (night vision, healing, buff) are bound to items in the “Aid” inventory menu so you can favorite them to use as needed, combat feeding, sun damage is present right at the start, includes craftable coffins for sleeping, includes a plantable version of Bloodleaf that harvests blood from settlers (somehow) which you can harvest from the plant in turn, two vanilla blood packs can be converted to a new bloodpack which will actually count towards your feeding (design decisions by the mod author to avoid compatibility issues)
Cons: Sun damage is wonky (during daylight hours if you are inside and stand under a bright light source you will take sun damage), no “gentle” feeding a la TES (feeding on friendly NPCs will always start a fight; you can and should sneak while feeding on friendly npcs as you can sneak away and come back later and they still like you), your “blood pool” decreases a little too quick for Khajiit’s taste (more so if use the vampire abilities as they are fueled by blood) requiring frequent feeding which can get a bit hairy if there aren’t any convenient Raiders around
Vasaki-
Pros: allows you to bottle blood for later (similar to the “dine and dash” cannibal perk from New Vegas), includes a “settings” holotape you can craft/insert via console that allows you to tweak multiple vampire options (such as rate of bloodhunger), vampire abilities are automatically added upon acquiring the perks for vampirism (you will jump much higher than normal, etc) so no activating abilities required
Cons: feed off the dead rather than the living (no feeding on the living at all), sun damage is activated by going a period of time without feeding and requires an additional perk besides the main one (accessed through the settings tape)
In Khajiit’s opinion,
Nuka Sanguinare does more to make it actually feel like a different experience rather than just a rebranded Cannibal Perk. It’s not perfect, not by a long shot, but it’s not bad considering. Vasaki is a decent mod too though. The inclusion of the settings holotape was a very good idea (wish Sanguinare had a way to slow down your blood cravings). Basically, it really just depends on what you want a vampire mod to do, and to Khajiit, Sanguinare simply checks more boxes.