Sieges are certainly a big draw, though; keeps and castles have considerable defenses in addition to the enemy players themselves. While it's possible to eventually destroy walls and gates by hand, you'll almost certainly need to employ siege weapons to speed up the process. This causes this great ebb and flow as players inside of the castles form up to make raids against the enemy's siege weapons, only to have the tide of players shift and be driven back inside again. I'd highly advise keeping a ranged weapon on hand though, or you're likely to get mobbed. One last interesting aspect to World vs. World is that player and monster kills still award loot and experience. While you won't be losing or looting any actual items, it does mean that if you so choose you can level entirely in the World vs. World zones by defeating players and discovering various points on the map.
If you're the sort that loves to fully explore a world, Guild Wars 2 not only offers an interesting setting but also rewards you for seeing it all. Every zone is littered with points of interest and vistas, and you'll accrue experience and items for finding them and for tracking down all 100% of them in a map. The vistas are especially fun since they frequently involve some kind of platforming, and in addition to the experience points, you're rewarded with lovely view of the surrounding area. Some of the most fun I had during the events was puzzling out how to get on top of something to reach a certain vista, and it's great that I'm not falling behind the leveling curve in order to satiate my curiosity and sense of adventure. It's just one more way that Guild Wars 2 separates progression from killing X number of Y.
For this final beta weekend, the last two races were made available. Both of them play on some existing fantasy stereotypes, but they are different enough to keep things interesting and not become straight rips from Tolkien. The Asura fit right in with the short stature, intelligent and slightly mad genius that gnomes and dwarfs might normally fill, but they draw from a very different aesthetic. Instead of steampunk, their technology has more a fantasy sci-fi feel, and they look more visually similar to Stich than to Gimli. Likewise, the Sylvari draw on many of the typical elven notes, humanoids that trend on the slighter body type and have a love for nature, but the Sylvari literally are nature. These sentient plants have a really interesting design in that while other fantasy creatures like ents are distinctly plants given motion, Sylvari's features are the plants themselves, like leaves forming the resemblance of hair. Between these new two races, the gigantic size of the Norn, the bestial look of the Charr and the blank slate of humans combined with all the various items transformations and dyes, you shouldn't have any problems constructing great unique looking characters.
While the beta is over, and even though I'll need to recreate my stabby thief Slycne again, I eagerly awaiting release. There are a few things that remain to be seen if they'll pan out favorably. For instance, we haven't seen what the end game is like and what engine optimization we can expect remains to be done. Overall though, World of Warcraft may have ushered in the current generation of MMOs, but Guild Wars 2 has the potential to carry the genre forward again.