Wow. Just finished it all. These are good. Like, really good. The least mechanically effective of all of them is probably the Reborn, which is still really good.
Let's start with the blurb about how they're changing races into Lineages, and what Lineages do.
I really like this. This should have been in 5e from the get-go. If they aren't going to change all of the current races to lineages through errata, they need to. WotC does this "half-in and half-out" thing with new mechanics. To quote Ron Swanson, "Never half-ass two things. Full-ass one thing."
If they do this for all the existing races, I'll be happy. If not, I'll be less than pleased, but will probably end up doing a DMs Guild product with all of the races as lineages in it.
Now, the Dhampir!
I honestly have never liked the Dhampir. I thought they were overrated and overdone. I still think that to an extent. However, this UA makes me want to play a freaking Dhampir.
Your speed is 35 (awesome!), and you can be Small or Medium. You also get Darkvision (standard), and you get SPIDER CLIMB at level 3, which is crazy good (not as good as flight, but still really good).
Then. . . your vampiric bite. This is great. Especially good for monks, because these are simple weapons, so the damage dice scales as your Martial Arts dice scales. Having attack and damage rolls being based off of CON is uh. . . may. . . zing and completely unique in 5e. Advantage on attack rolls with it when you're at low HP is great, but makes it kind of suck that this isn't finesse (imagine Sneak Attack biting every round!), but is really potent anyway.
The ability to regain hit points or make yourself more accurate with attacks/skills is also great, and very nice to see in a non-broken way on a Dhampir.
Overall, this (race) lineage is really good. It got rid of my previous contempt for Dhampir, which I didn't think was possible. Time for me to go make a Dhampir Shadow Monk!
The Hexblood is . . . interesting. I never would have thought that we'd get a Hag-spawn (race) lineage, but this does it pretty well.
Fey Resilience is worded . . . weirdly. They need to just copy/paste what the Elf/Half-Elf race has.
Hex Magic is good, especially for Fighters and Monks, but really for everyone. I especially love being able to use your own spell slots to cast these spells, which is something that needs to be added to every single previous race that could cast leveled spells.
Magic token seems crazy potent with the right combinations, but doesn't seem like it will be game-breaking (most of the time).
Yay! WotC actually listened to us (for once)! The Revived Rogue was split into two, one being a ghost-y Phantom Rogue subclass, and the other being the Returned Lineage! Nice!
Frankenstein's Monster. This race is halfway between Frankenstein's Monster and a Zombie/Wight. Not complaining, though. The Armorer Artificer is based off of Iron Man, and it was made well.
Darkvision! This is standard, but doesn't really fit the "construct" origin of this lineage. Deathless Nature is amazing, and I'm definitely stealing this for my Vezyi and Fehntüm races. Knowledge From a Past Life is also really, really good. I want to play this race. It would work extremely well as a Spirits Bard (gathering stories from all of its previous lives) or Undead Warlock (serving the undead master that created you!).
Final Thoughts
I like it. This is great. I love that they used Proficiency Bonus for amount of uses each long rest, which I'm sure some others will also appreciate. This looks like they're going in the right direction. As soon as they announce whatever book this is coming out in, I'm throwing my money at them for the setting and these races/lineages.