I've bought, played and enjoyed Guild Wars 2 and the primary reason for that is the WvW mode. A server goes up against two other servers in a massive 4-map-sized game of king of the hill. One map for each server's "home" territory and one map as the "Eternal Battlegrounds". Fighting over camps, towers, keeps and castles nets your server control of it and every 5 minutes your server gains a certain number of points depending on the size of your capture. At the end of a week, the points are tallied up and whichever server out of the three has the most, wins.
Laying siege to castles by building trebuchets and choking off reinforcements is incredibly epic. Defending a castle with a squad of 10 against 50 players is intense, but doable. But personally, I like working with a small team. I play with a tight group of friends and we're fairly capable of hitting unguarded supply camps like a squad of Navy Seals, getting the points, killing whatever straggler gets in our way and getting out.
So far my main character is only level 20, but because of the way PvP works, while my gear is still the same, when I enter WvW mode my stats goes up to match a naked level 80's (the max).
I'm not capable of devoting a lot of time to GW2 and I'm at a disadvantage when I only have level 20 gear, but I manage to pull through with the help of teamwork and skill.
I've never played the first Guild Wars, so don't ask me how it compares to that, but so far I really like the sequel.