As the title states, I would like to know the biggest changes between the two systems, both mechanic-wise and story-wise. Why should I choose one over the other? (And please, don't use "Vampire: the Requiem is still supported by WW" as a argument.)
Mechanically, I think there are really only three big differences.
First is that spending a point of Willpower in Requiem grants you three extra dice on the roll rather than an automatic success, which is a very big deal.
Next is that botching (or "dramatic failure") just doesn't happen as often in the new World of Darkness system. Dramatic failures only occur when you are reduced to rolling a chance die (one die that only succeeds on a roll of 10) and it comes up a 1.
A relatively minor difference related to that is that success really isn't measured in degrees in the new system. You either succeed or you get an exceptional success. The Storyteller has to declare bonuses or penalties (which grant or remove dice) prior to the roll.
The third big difference is that in combat, damage is figured directly from the result of the attack roll. It's faster, but it can be a lot deadlier.
In terms of the story, the Masquerade setting is gone. Requiem focuses much more closely on local action compared to Masquerade's global tone. Clan infrastructures like the Nosferatu's intelligence network just don't exist, and most vampires align themselves with philosophically like-minded covenants.
If you never played Masquerade as anything but a city game, I don't think you'd find it much different. There are some interesting changes to how the vampiric condition works, though. They get more powerful with age thanks to Blood Potency, so lineage doesn't matter as much. Also, vampires instinctively recognize the Beast in each other using a system called the Predator's Taint.
White Wolf has published a good translation guide for playing Masquerade with Requiem or vice versa.
I'm actually using that guide to run my Masquerade game using Requiem's rules.
Hope that helps!
A few of the prominent changes:
- In Masquerade, difficulty numbers would range up and down the scale, from 3 all the way up to 9. In Requiem, the difficulty is always 8.
- In Masquerade, the dice pool to activate a discipline was formed from a combined Attribute and Ability. In Requiem, the level you possess in that discipline is added to it.
- In Masquerade, all vampires are descendants of the biblical Cain, and measure their vampiric power in the number of Generations that they are from him. In Requiem, the Potency of a vampire's Blood is something they can raise with experience, and each clan has its own origin story. (In fact, there are hints in the clanbooks that suggest that all five clans are actually separate kinds of supernatural being with some common connections.)
- In Masquerade, bloodlines are rare and unusual offshoots of clans. In Requiem, bloodlines are more common, and can be joined or designed by vampires of sufficient power intentionally.
- In Masquerade, the blood bond always forms after three drinks. In Requiem, the number can be more, and is uncertain.
- In Masquerade, vampires don't recognize each other on sight; in Requiem, the Beast makes the presence of another vampire and his comparative Potency obvious without concealing arts.
You might choose Requiem if you wanted a game of various competing political factions and greater intra-group conflict. Requiem is also a much "dirtier" game than Masquerade; the glamour of the '90s (almost '80s) vampire world and its global conspiracies gives way to a grungier, more visceral modernity.