I finally am close to finishing the single player story on the default mode (i have almost no time,hurray kids). It's not a bad game. It's basically D2 with different skin, storyline, and acts. I like the voice acting. I like the little bits of dialog from your followers (granted this never seems to go anywhere, complete waste). I like the visuals, i like the ease of getting into it. It's an incredibly simple game at its core, and that really appeals to me right now.
I play a DH and i am hoping to get to level 40ish so i can get a ferret companion, I thought they were a nice touch, homage to WoW hunters. I can also see the appeal of other classes, and the game is short enough to allow some replay value.
Granted, there is alot not to like. The constant lag and tethering, I am not sure if its my video card or some really fucked up network connection (WoW runs fine for me), but this is my #1 complaint.
The AH, i never have seen it. I could care less. To me this is a short single player game with some multi-player. I know some people really like the farming aspect, but to me this is not an MMO, was never designed to be a game that you sink 100s of hours into.
Also the absurd price and inability to sell the game sucks royally. Since blizz is holding all the cards on this i expect the price to be high for a long time, unlike typical games that drop by 1/2 in six months.
But given all that, the story is interesting and as a simple shooter type game, it's not too bad.