The Temple of the Jade Serpent is the first of many dungeons we'll be encountering in Mists of Pandaria, and it's currently the only one open and available on the beta servers. The dungeon is fine at level 85, and if you've managed to level through the Jade Forest and hit level 86, there's a wonderful guy at the front entrance (pictured above) who will sell you a variety of items. These include higher-level bandages, any glyphs you might be missing, and Tome of the Clear Mind, Mists of Pandaria's version of Dust of Disappearance for those level 86 or higher.
If nothing else, I'd recommend popping in here just to visit Flaskataur, say hello, and purchase a few things. But that wouldn't be anywhere near as fun as running this starter dungeon. Fast, precise, and to the point, Temple of the Jade Serpent is nothing like the sheer length of Zul'Gurub, and much more like the shortened length of dungeons like Vortex Pinnacle, minus the travel time. In short, it's perfectly ... well, short!
Warcraft is a game that seems fairly straightforward in faction division. Alliance is good; Horde is bad. But once you delve into it, that straightforwardness becomes muddled and marred. The Alliance may seem like good guys, but they have their bad moments, and the Horde may seem evil, but even they've got their shining examples of goodness buried within. And when you examine the story and lore closely, you begin to realize that there is no black-and-white division between good and evil; all characters are loosely scattered and somewhere in shades of gray.
Sure, you can argue that the orcs are evil -- and they absolutely were, back in the day. But when you start looking at the justifications for the orcs' actions, that label of pure evil comes into question. As for the Alliance, you can argue that the human race is a bastion of goodness and light -- but then you look at things like the Scarlet Crusade, at Benedictus' betrayal, and you begin to wonder whether the human race is inherently good or just as scattered as the rest of the world.
... Unless, of course, you look at the one place where evil characters always hang out: instances.