Well, it's a good game but isn't a classic like other Blizzard games. It has nothing on Diablo 2.
Also, personal gripe about it. They screwed up Diablo's character design. He looked like a WoW demon chick more than he looked like the badass devil from the older games.
But with that said. I am not playing anymore games that follow that game model. The Multi-player RPG Game that allows you to level (Borderlands, Diablo and so on). I always get left behind by my friends and once I do, I will shelf the game a few hours of solo play.