It's a great game. The best graphics I have seen. The accent is on PVP or GVG (Guild vs Guild), I mostly play the PVE (player vs enemy) You don't have to pay to play it either. Like DS, you can create a character to be warrior, healer, archer etc. There is not a single player, like on DS. The only thing I do not like about it is, if someones leaves your group, no one else can join your party. Only in the towns, can you pick up another player.
It has a good story line, and many many quests to complete. They just added two more areas, and more are planned. You have to work a little bit harder to control your character. The best part is that it cannot be hacked. Also, in chat, swear words are censored. You can only see "----"
In the GVG, you even play against other countries. If your country has "favor" (meaning they defeated players from another country), you can go into other areas, where all the best "goodies" are. You do not have to join a Guild, but it's better if you do.
Very cool :) I also prefer the Player vs. Enemy/Player vs. Monster type of games.
Countries going at it? I have done that before. In the mecha game Heavy Gear you could do that (although the countries were imaginary, being the CNCS and AST which was parellel to NATO and the Warsaw Pact).
Hacking was a big problem in Diablo, although swear words never bothered me.