It's insane how much better the AH is now. You just buy the item you want, at ANY amount you want, and it's always the cheapest price. No more buying out all these weird stack amounts when you just want X amount.
Same thing with selling. It's just two clicks now. No more needing to look up how much the item is going for and manually typing in the price.
It's fantastic. I can't believe we've been using that awful original AH for so long.