Finally picked up Neverwinter Nights 2 yesterday. After much anticipation, ever-changing release dates, and stocking issues at Ye Olde Beste Buye, I finally brought home the (unfortunately) CD-ROM edition.
Initially I had some problems - after install, I could update and launch the toolset, but if I tried to launch the game, I'd get an Unable to authenticate disc error.
Atari's support site doesn't list NWN2, and in order to contact them, you first have to select your game - I sent them a message under NWN, but it told me that it'd be 7 - 10 days for a response. I double-checked the readme, and it says you can send your error logs to SecuROM; I sent them an email after business hours, and got a response the next afternoon. They recommended a DVD drive firmware update (the only thing I hadn't tried at that point), which has resolved the problem solidly. However, there are numorous people on the forums for whom even this did not resolve the issue - hopefully this gets fixed in a patch later.
All in all, it's a really nice game, with very good quality graphics. They're smoother than the graphics of Oblivion, but more cartoonish where Oblivion makes some vague stab at realism. All in all, it's a solid update to the original NWN. However, it's important to note that it's a complete rewrite, no code spared, so the entire UI has changed.
The UI more customizable than before, but feels a little clunky. The new targeting system has some bizarre qualities, and I found it confusing for a while that you can attack something without targeting it, and target an enemy while doing nothing to it. I also much preferred the old context ring menus from NWN1 to the new delayed-reaction drop-down menus of NWN2. I know, I know, more than half prefer the new blah blah blah.... how much more than half? If it's a small margin, you should sit down with your testers and come up with a way to improve the system, or you offer it as an option to players.
As far as gameplay goes, the engine is a solid representation of D&D 3.5, including prestige classes. Note that it stops at level 20; no epic classes yet, though I'd put money on epic levels coming out in an expansion pack, as they did in NWN1. Mounts are NOT present either; if I remember right, this was announced to come in an expansion pack, though I can't think of the source off the top of my head.
I haven't yet completed the original campaign, however, I will say some about it. The story is pretty good; however, as most western RPG's do, it goes for breadth rather than depth. You have total control over your character, the star of the show, and their actions and decisions; thus, they've spent more resources on increasing your options than they have on developing a deep and engrossing storyline. Take Oblivion as a more extreme example - nearly a "sandbox" game, it sacrifices depth of the main plotline to offer a greater array of options and side quests. Compare this to a Zelda or Final Fantasy title, where they provide you with a character, and a fairly limited set of options, but a much more in-depth and engrossing storyine.
As there aren't many NWN2 servers out there right now, I'm holding off on reviewing online features. Online play was my favorite part of NWN1, with the capability to create a complete world from scratch and run a persistent world being a significant draw for me. So I have high hopes for NWN2 in the same areas, but only time will tell.