Game, set, MATCH!
You can control up to 4 partymembers (including your character that you select at the start), each having different stats, different looks and different stories. For example, one of the first that you encounter is Rhulana, a female warrior that obviously prefers fighting over talking, but she can come in handy with the first quests that you encounter.
These quests (at the start, though) are the standard errand boy quests (Kill X of this, bring me Y of that) but it changes soon (I won't give you examples as I don't want to spoil anything :)).
Spoilers are, by the way, the least you can use as the story that develops in front of your eyes is one of the best that I have ever seen in a game (the only game that had a better story that jumps to mind is The Witcher by CD Projekt). You will play the detective, find and kill murderers in a city that is very much 'alive'. The characters have their own scheme of the day (going to the herbalist, talk to other people) while they are to be found in their beds at night. This is something extra so you are more easily drown into the game.
Overall, this is one of the best RPG's that I have played recently. I give it a 8.5 because no game is perfect, and there are still some bugs that need fixing (quests that do not end, corpses that just vanish before you can loot it, etc.)
If you're a fan of RPG's, this is a must buy. People that like to see more action, are better off with a good multiplayer FPS...