Well, since I've been running regular WoD LARP games since '96 or so I guess I should throw in here. In essence, I think it comes down to the same with just about any other game- the quality of the game is going to depend on the people involved.
Unfortunately, I can say that I've seen a lot of what AFGNCAAP is talking about in our game as well. Especially with the more experienced players. There definately does seem to be some sort of Rubicon in which formerly-good roleplayers get too big for their character sheet and start throwing their weight around IC. The clique-ish type feel to it at times, especially when real life friends just draw up a variety of characters that have no real reason to be together ("Wait, why is the Seelie Troll acting as a hitman for the Prince? This makes no sense...")
Even though we run an ongoing game, we only run at conventions (say 2-3 times a year), so the setup is a bit different from a lot of typical ongoing games. One thing this does for us is ensures that we get a fair amount of new players, people who just came to the con and wanted to play a LARP. This helps stir things up as well, since it's not just a case of older players and groups brining in their friends to help shore up their numbers. I personally think that the way the organizers handle the incoming new players is one of the biggest deciding factors in a LARP. I've only actually been in a few as a player myself, but in every case I was pretty much lost in the shuffle with all the ongoing plots that the veteran players had. That's why we try to ensure that new people coming in will get hooked into the action in a way that won't get them immediately killed.
Aside from ST-generated plots, such as "bad Pentex guy comes to town", we try to keep things as player-motivated as possible. Unfortunately, this does mean that problems can occur, like overpowered characters dominating the game, or people doing disruptive things because "it's what my character would have done" (this has got to be the most common excuse for twinkish behavior that I hear). But it also means that PCs can go for things they couldn't in tabletop, such as becoming Prince. We've had one regular game that's been only PC princes and primogen for a few years now, and even if the Princes do tend to be short-lived, there's still plenty of people trying for the position.
We don't do this through any sort of status system (which is really what turned me off to the Camarilla's setup)- in fact, we don't have any social mechanics at all. If someone wants to get a favor done, or get a Primiogen position, or unite two different camps or whatever, then they have to go out and do it in the game. They aren't going to just show up and declare themselves Prince due to being strongest gen or something (though we've had people try; they were universally ignored). They have to convince other people to support them for Prince, and make sure that the guy who is in charge doesn't get wind of it. Really, it's almost a simulationist type of setup; this is probably one of the main reasons that I like running it, just sitting back and seeing how things play out. Again, all this can lead to old political problems, but at least they're generated by the players in the game, as opposed to ST politics and favoritism (which has been a problem in just about- no, I take that back, in every Cam game I've been too).
If nothing else, I can take pride in the fact that we don't use MET.
And, now that the WoD is ending, we won't be using that any more either, since we wanted to neither restart the game nor put it on hold for a year while WW gets their new books out. As someone who's had to take things like Mage and Changeling 1st eds and work them into the game, I can honestly say that it's a major pain to try and get everything to gel (and, after Changeling, we just didn't bother any more).
Well, I think that's about all I've got for now. I'd say that if someone is wanting to try a LARP, but is put off by the some of the more negative stories, the best bet is to try a one-shot game, such as is generally run at conventions. Find some acquaintances who know the scene, and can give you an idea of what to expect. Also, talk to the people running it, sound them out and see what kind of vibe you get off them, same as if you were looking for a new tabletop group. All this should at least give you some idea of what you'll be getting into.
