I started playing this game years ago but didn't finish it, so I recently decided to replay it and actually get all the way to the end. In many ways, it's one of the best games I've ever played. In other ways, it's shit. But overall it's very much worth playing.
The Good Bits
Mostly, the first half of this game is excellent. When I think of computer RPGs, I think hack-and-slash tedium, but VtM:B avoids this really well. There are a wide selection of abilities that allow for multiple solutions to problems, including several options for non-violent resolutions, such as persuasion, deception, trickery and sneaking. You can just go in guns blazing, and sometimes screwing up one of the other options leaves you with little choice (unless you reload), but for most of the game it's pretty easy to avoid violence. And the nonviolent solutions are often interesting and more rewarding.
There's also a lot of interesting dialogue and background information about the setting to be found if you don't just kill people, and many of the subplots and side-quests are really well-written and engaging. Basically, everything in the first two areas of the game (Santa Monica and downtown LA) is great. There's a huge amount of detail and a ridiculous number of things to do, regardless of how you choose to approach it.
The Bad Bits
Then you get into the sewers of Hollywood and it all goes to shit. The game up to that point has had a pretty realistic environment with streets and buildings that look like they were actually built by humans, for humans. The main sewers also seem like they could be real sewers. I don't actually know what real sewers are like, but I could believe that there are sewers like those.
But then you get into the sealed off section of the sewers and insanity breaks out. There are numerous places that a human just couldn't get to and control systems that don't make sense. There are places only accessible by swimming through underwater tunnels, and one particularly notable bit where the underwater door you need to get through is only open when there's a huge rotor going that pushes you away from the doorway. Who designed this? How was it ever supposed to be maintained?
This is also the bit where the game forgets it's a character and dialogue based RPG and turns into a FPS. You just have to kill endless hordes of mutant vampire monster things.
It does pick up a bit again after that, there are a few more things to do that don't involve violence, but then it loses its way again and you just get three or four more missions that involve nothing but killing hordes of dudes. And if you got the skills you need to get through the sewers, the rest of these are a cakewalk. Particularly as most of them have handy humans to snack on as you go.
Then there's the werewolf. You can't kill it, but it can kill the fuck out of you. And your goal is simply to survive for a set amount of time, then get to the escape point. Technically I cheated to get through this bit, because the werewolf got stuck in a doorway and kept glitching, and I just stood there and waited for time to run out, but I consider it justified as that mission is just bullshit.
Then there's the final boss. Technically you don't have to fight her, you can join her team, but if you do you end up dying in the final cutscene, so I'm not sure that should really be considered a valid option. I'll get back to that later though.
So you fight her, and she is so absurdly powerful that after killing the hell out of previous bosses without much difficulty, I managed to get her down to 2/3rds of her total health before I ran out of all my health items and just went "Fuck it, god mode".
After suffering through the final parts of the game, that are themselves a total letdown after what came before, you finally get to the ending. And it is so not worth it. Throughout the whole game various factions have been keen on getting this sarcophagus that supposedly contains something incredibly powerful. If you join the Camarilla or the Kuei-jin, you don't even find out what's in it, it just ends. "Well, that was a thing that happened, anyway, on with our lives." If you join with the obviously evil Sebastian Lacroix, the Anarchs or just go your own way, you find out that the sarcophagus contains... a dead guy. That's it. The whole thing is about an ordinary, non-magical, dead body. Oh, and if you join Lacroix or the Kuei-jin, you die. Sucks to be you, I guess.
Strangely, after revealing that she isn't going to let you join her team after all, the Kuei-jin leader, who has you totally at her mercy at this point, says that she isn't going to kill you, just that she doesn't want you around. And then she kills you anyway. I don't understand why she even bothers to say she's not going to kill you. She doesn't need to trick you at that point, she's already won.
More Good Bits
After those last two sections, it might seem like I wouldn't recommend this game, but that's not the case. It is incredibly fun most of the way through. There are a few minor annoyances at times, like the fact that the available dialogue options don't always allow you to be 100% loyal to whatever faction you prefer to work for. I was aiming for being Lacroix's loyal minion, as he seemed like he was going to be on the winning side, but it seemed like I was railroaded into being not quite loyal enough to escape his raging paranoia a couple of times, most notably when I wanted to report to him that the Kuei-jin agents were claiming they had an alliance with him and the closest option I had to that implied that I believed them. Which was irrelevant to me, because I didn't care who he was allied with, but he takes this insinuation as disloyalty.
But mostly the dialogue options give you enough control that you can do things the way you want to, be a dick to people or be friendly, help people or ignore them, or offer to help in exchange for payment. Or actively go out of your way to prevent them from getting what they want.
And the background detail in the world is really great. There are all sorts of humourous things hidden away on computers that you can hack into, and the early parts of the game are even worth a second playthrough as a Malkavian (assuming you didn't pick that clan the first time) because there's quite a bit of bonus content due to your character's insanity, such as the news anchor on TV addressing you personally and various hints about things coming out due to your prophetic visions.
I actually played as a Malkavian the first time through (I don't really know the setting, so I let the computer choose my clan based on the personality quiz) and it really adds an extra layer to the game, although the cryptic nature of much of the player character's dialogue in that mode can make it a little confusing, but not insurmountably so.
The version of the game that I got came pre-installed with the Companion Mod, and I cannot recommend this enough. As well as modifying a couple of NPCs so that they can willingly choose to join you in your missions the mod adds an item that allows you to enslave people against their will. The extra dialogue for tricking people into performing the required action and then becoming your slave is added in seamlessly and shows that the mod's creator was just insanely dedicated to this project.
As well as being really cool, the mod makes some of the more difficult missions a bit easier, because you can enslave some other vampires and they can assist you in combat, and you can get access to extra abilities through them. Playing as a Gangrel with essentially no stealth abilities I found it incredibly helpful to be able to access a Malkavian's ability to turn invisible to do some of the missions where keeping a low profile was required. I guess this could be regarded as cheating, but if that bothers you you can still do the enslaving bit and just command your minions to stay at home. Plus then you get to play with them like dolls, which I found entertaining.
One thing to be careful about though is that some people who give out quests can be enslaved, and you want to be sure you don't enslave them before their role in the game is done with, otherwise you'll miss out on some content. I don't think it's possible to enslave anyone who still has plot-critical quests to give you, but the side quests are generally the more fun ones anyway, so missing them would be unfortunate.
If you do decide to play this game (which you should) there are basically two ways I'd recommend going with it. If you don't mind cheating, just play the early parts the way you want to, because putting XP into non-violent skills opens up some interesting options, and then you can cheat to reassign your choices later (or just max out your fighting skills for free, whatever) .
If cheating bothers you, be prepared for violence. There is no way to avoid it later in the game, you are going to have to kill fuckloads of dudes, so get some combat-relevant skills.
Oh, and remember that the ending is shit and it's not worth playing through just to see it if you're sick of the game. All the endings are on YouTube if you're really desperate.