For most things, I like Revised edition. For one thing, I have almost all the books. (in storage due to limited shelf-space in my apartment, but I do HAVE them). It’s also the edition I wrote for – both in Vampire: the Masquerade and Dark Ages: Vampire.
There were some pretty ridiculous things published with the earlier editions. They weren’t as well planned, they weren’t really designed with an eye to building a multi-book, internally consistent universe with plausible limitations. Which is understandable; no one expected Vampire’s World of Darkness to GROW like it did, and spin-off six or seven other whole games as well. Very few games prior to Vampire (short of Dungeons and Dragons itself) had captured the imaginations of gamers, not to mention the market share, that Vampire did. The Storyteller rules system and the whole idea of the Gothic-Punk World of Darkness, and of course, the perfect timing of the re-animation of the popularity of Vampire fiction as a genre—all worked in their favor. But it did have flaws—so building on that popularity, and to build on the lessons learned in developing the Storyteller system even further, revision was needed.
Revised Edition was much more coherent. Rules were re-worked to better even out the development of learned abilities and supernatural gifts, and how they could be used, and to allow for all the other supernatural beasties (Werewolves, Mages, Ghosts, Demons, Fae, etc.) that also inhabited the World of Darkness. The history and culture of the Camarilla, the Sabbat, and other clans were much better balanced and thought out. In particular, a lot of the racial/cultural stereotyping of foreign clans like the Ravnos and Assamites, etc. got a very necessary re-design and re-imagining. (There were some earlier edition books that were just embarrassing to read, let me tell you). And the planning and development that built and expanded the world—supplements, players’ guides, city books, sect and clan books, etc.—was done with an eye to building a whole universe, so there was some serious effort made to maintain consistency and balance from one book to the next. (They didn’t always succeed, but they did at least try).
Alas, eventually they decided the world had grown about as much as it could (or at least as much as the developers could stand), and so they decided to let the much-prophesied Armageddon actually happen, across ALL related game lines. It was a bold decision, and they carried it off very well (I’m biased, of course, I helped a little). But it was kind of disappointing too (not just because I had contracts and potential contracts cancelled). It was such a vast world, so much more to explore, if your focus is on a character-driven chronicle, drilling down into the night-to-night details, rather than seeing the world as one big epic meta-story. I wasn’t done with it yet. We’ve never played any of the Gehenna/Last Nights stories; our characters’ stories still have other places to go. (I know which one I’d like to use, but we’re no where near ready to go there yet).
Then they came up with a whole new World of Darkness with Vampire: the Requiem, but that one just lacked the color, variety and depth of the original. The rules system was better (as a general rule, rules systems are always evolving and improving), and it did have some very good ideas in it (I liked the Clans/Covenants matrix in particular) but the world itself was… uninspiring. It was really more a toolbox than a universe, very flexible and customizable, but lacking the colorful characters, over-arching meta-plots, and detailed world-building and historical background of previous editions. Which was their intent, so I can’t fault that, but for me – Vampire: the Masquerade, Revised, will always be the REAL World of Darkness.
(I like V20 too, of course. It does have better rules, but I don’t really use rules to such a degree it matters. But what I really like is having EVERYTHING in one book, which is a lot easier to use as a reference. And it’s a really pretty book, too.)