I'm playing on the PS3 and I'm having fun. Been playing with my friends, and we had our old saves from the original copy, so we were able to just transfer our characters over. Needless to say, we're kind of crazy overpowered already. And our trophy lists are completely messed up. We've defeated Diablo already and have his trophy, but all the bosses before him are still locked because we're able to jump anywhere in the game.
I am loving the new loot drop. In the original, I would spend hours and hours farming for better items, or pieces of ANY legendary set, and I would consider myself lucky if I found one piece. Now though, I already have two pieces of Natalya's set for the Demon Huntress, and I've been getting plenty of other legendary drops. It's much more rewarding now.
I'm also liking that they are continuing the leftover plot threads from the first game, namely your companions and Shen. I'm glad I got more information on all of them.
My only complaint is that the second boss in Act V felt...lacking. I was expecting more of a confrontation than what I got. Not more of a fight, mind you, but more dialogue and stuff. It just seemed rushed, and therefore felt a little out of place.
Oh! And this new nemesis system is pretty entertaining. We killed Diablo and we were talking to everyone at the end of the game, checking our loot, when this monster who has killed me three times popped up. My friend was still stuck in the conversation mode and was slaughtered. Meanwhile, I was frantically trying to get out of my menu and yelling at him, "What did you do? Why are we being attacked now?" It wasn't until I was able to run away and saw the monster's name that I understood what had happened and I thought it was hilarious.