I tried the PVP battlegrounds, El Dorado and Stonehenge for the first time yesterday. They are both timed maps with a set number of players per team. For El Dorado, I think the limit was around 20 players per team/faction while Stonehenge was 5 per team/faction. For these two PVP maps you can queue as a party or join solo.
In El Dorado, you run around the map and collect these "tablets" that help your team accumulate points. Your team (and individual players) can hold multiple tablets, and the more tablets you hold, the faster your team accumulates points. It's kind of like Capture the Flag and Team Fortress except that the capture points are moving targets. As usual, all three factions compete, so there is a constant 3-way battle going on.
Stonehenge plays out like a game of King of the Hill. Your team of 5 players must control the center (Stonehenge), to accumulate points. The other two factions have the same objective so it is a constant battle. Teams can be largely imbalanced if you end up without a healer or have a majority of under geared players. In addition, players with AOE attacks seem to have an advantage.
For both maps, at the end of each match, you are greeted with a completion scoreboard that tracks a large number of statistics with score focused on points rather than kills (like Team Fortress). You can see number of kills, number of deaths, amount of damage dealt, amount of healing given, territory controlled, etc.
I would love to see them add more dynamic elements to the existing gameplay to make PVP more engaging -- thinking along the lines of TF2 here (announcing kill streaks, nemesis system, item drops, player customization, etc.). An in-game leaderboard that ranks different player stats for overall, faction, and cabal, would be nice too.
These two maps along with the persistent PVP in Fusang Projects make for a really good foundation for organized PVP. When you bring up the PVP menu, there certainly seems to be plenty of room to add other "themed" PVP maps to different locations, and I believe I read somewhere that they are currently planning a "PVP Dungeon". I will be looking forward to any additions or improvements they make. This is something that could keep players interested and playing for a long time.