Until unclehobart adds his opinion, I´d like to give out mine.
NWN cant decide wether it wants to be a full fledged Solo-RPG or a Multiusergame. In neither aspects it fullfills its role.
Solo: Recent D&D games amazed me with their ability to reduce the roleplaying to "walk into the nearest dungeon and slaughter everything". What character you choose has no effect on the game at all, not to speak of alignments. The plot sounds interesting, but suffers from enormous logical abhorrencies (A Druid asks you to free the animals from the local zoo. In order to do this, you kill all employes in the zoo. Before the eyes of visitors and without interference of the guards in the city. They simply dont care)
Game mechanics are as good or bad as D&D 3rd edition is. Depends on how you like them. I detest them. What for is a multiclass system when it only helps to weaken your character (Especially because 20th lvl is the cap).
From the isometric view to the endless carnage I felt reminded of Diablo.
Multiplayer: Well, in theory you can play any number of sceneries from players around the world. In reality, good modules are rare to find and even rarer are the players who play them. Character advancement is meaningless as everybody can make a Lvl 20 char in a few minutes. As an EQ-player i find this disturbing in the least, because whats the point in playing the damn thing?
If you enjoyed Diablo, you might have fun, but if you look for something in the spirit of Baldurs Gate or even Planescape:Torment (*sigh*), then be careful please.
My 2 cp