Well guys... being on the beta like Packmule.org I have tried DS on a p2-450 and a p4-2.2ghz... Low res and max res settings. There is a difference in detail, no doubt. At full detail the little touches amaze you. There is SO much vegatation, flowers, trees, and little things that you awe in every little place. Just as example, in 1 dungeon there were lots of little little spiders all running around the big spiders... just there are little details. Granted you won't see this detail on low detail settings. It really fleshes out the game. Granted it IS NOT Diablo... It seriously plays ALOT like Darkstone, which is not bad at all... It does have limited skills but focuses more on spells later on in the game.
The engine, bar none, is revolutionary. I have played numerous times to just realize having NO level load menus in game, that I just spent over 3-6 hours playing and didn't even realize it!
The biggest aspect is not the 40-60 hour single player game... it is the multiplayer game that is supposedly DOUBLE the size of the single player game (which a completely different set of maps/levels/dungeons/etc). Also the engine is mod ready... So people can mod this out of the box...
You can't do that with Diablo or Darkstone ...