Does not live up to the series, a sheer disappointment.
Graphically, it's beautiful. Sound effects are also excellent.
The story, garbage.
The servers, garbage. If you play a Hardcore character (one where death is permanent), you can do everything perfectly and still lose your character to random server crashes, lag spikes, and rubber banding.
In other Diablo games, you would farm for gear that is for YOUR character. In Diablo 3, what you find is completely random and may not even apply to your class. This is because the real money auction house is implemented to stimulate each player to contribute to selling items. The sad thing is, if you play Hardcore, the real money auction house is not implemented. Yet, you are stuck with the same loot scheme as non-hardcore players.
The Legendary items may as well have been the lowest stat items in the game. Blizzard is in the process of "fixing" this. On the same note, the gear is dumbed down to basic stats and basic gem allocations. It pales in comparison to Diablo II.
Overall, I am extremely disappointed with this game. The gameplay is decent, but repetitive. Your character is a gear check on higher levels, and you will grind the same acts with better gear to search for legendary items that are worse than lower quality gear (and it may not even be for your own character). The servers are unplayable right now, and if you want to make a Hardcore character, it's highly discouraged.
Save your money until this game is out of Beta.