Once you reach level 8 - 12 it is always a good idea to seek becoming a Vampire. Though there are a bunch of side effects the strengths that come with it are worth it. That is if your GM allows this.
In AD&D, I only fought one once, and I was playing a troll PC at the time.
I had managed to reduce him to fog or whatever, and he was about to fly away, so I did the only thing I could think of and inhaled him. I critically succeeded in my CON check and basically absorbed him. Which gave me a vampire troll. That was a fairly awesome character, but wasn't my intent, and had a lot to do with GM fudging.
Given a by-the-book fight with a standard vampire, even with my troll PC, I rather doubt I could have survived it one-on-one, objectively. They make them TOUGH in D&D circles, I'll give them that, and a lot of variety, Egyptian, Slavic, "Cerebral" (that can summon a flock of seagulls and looks like the lead singer of the group of the same name) etc.
Guess that goes right back into game rules and interpretations.
I can see weres being more easily translatable into PC 'races', as it is more an illness, a physical thing, almost an allergy, a reaction, a haywire instinct, they're just partly bestial, but have no particular alignment or intent change for the most part (at least they didn't used to), except for being amoral probably, just more concerned with more nature and animal-like issues and views of the world. There are some stories and basis of the werewolf being devilish and evil but overall I think lycanthropy generally gets a pass more into the mutant category, overall, for most people.
Vampires are definitely of the more sinister and even "undead" category, which is generally universally loathed by all living things. Only the few popular stabs at romanticizing the things, including Stoker's original that started it, and Anne Rice and, on from there, which are somewhat fairly recent (more or less) have a more humanistic "not so bad" approach to vampires, but unfortunately, those are the ones that have also gotten popularity FOR vampires, because it gives them some character, as it also presents them with weaknesses, flaws and personality, motivations, etc.
Pretty much before this was just Nosferatu, which I still think was awesome and also had all these failings, but was just so hideous and obviously monsterish, you just couldn't appreciate his "humanity" in the same way and sympathize. And rightly so, in some ways, as THAT was a vampire - but instead you go the Stephen King way, the Lost Boys way, it gets diluted.
But people who play games, who want to BE vampires, or play them in games, they want all the awesomeness of all the best parts of a vampire, sucking blood, speed, strength, flight, transformation, charisma, spells, hypnotism, telepathy, but they don't want to have to have to feed or not be able to go around in the sun, or be allergic to garlic or silver or not cross running water, etc, etc.
They want to play Blade or Angel, they want to be "daywalkers", they want to be immune to this and that - essentially they want to be superheroes, always the exception to the rule - also known as "munchkins", in my opinion. I think THIS is the kind of thing, these types of rules, are what are put in place to keep players from abusing and adopting certain monster races as their own - these kinds of drawbacks are the kinds of things that SHOULD cripple a player being able to just be Mr. Super Cool Everything and make him really have to think and make sure he wants to try to play a vampire. Playing something awesome like that, unless the whole game is based around everyone doing it, needs to be done as a compromise - sure you have super strength - you also can't enter blessed ground. Sure you can fly or whatever, you also take double damage from silver and take fire damage from being in sunlight, etc. Alignment is just, to me, academic, at that point - if it comes to the point where a GM has to point at alignment as to why someone can't play a vampire, he and/or his player has already missed the point.
I'd just like to say I think vampires being able to impregnate someone is possibly the most laughable thing I've ever read in fiction. There, it's out there.
I wouldn't want to be changing my character to a vampire at anytime. I want to like fight those things not become one.
If people want to play a evil campaign I can do that as a GM. I have no problem of people playing evil characters but I will still not allow you to be a vampire. I view a vampire as a evil creature and not one that can be played as a PC. IF you want to be a anti-paladin or a evil cleric go right ahead. But remember evil characters only go along with those who are stronger than they are. IF they are around the same level/power they will fight to gain the power over others. That is the nature of the evil beings.