I haven't had much time to play yet, but HOLY this is the most polished game I've ever seen. There are so many little features and details everywhere, that it's hard to believe this game is real. It feels like Blizzard finished the actual game about 4 years ago and spent every single day since then adding on extra bells and whistles to make it even more detailed and entertaining. This is the exact opposite of a game that has been rushed out the door. This feels like a game that had absolutely no release deadline and was simply worked on until it was finished in every possible way. This is the epitome of a focus on quality above all else. I am amazed at how solid this game feels. It could well be the single most 'complete' game OOB that there has ever been. (Keeping in mind I'm about 5-6 missions through the SP campaign.)