Played a lot more over a neato 3-day weekend, and I've definitely been taken in by the game. Otoh, I practically tore out my hair over some of the criminally-stupid quest design. For every high, like the defense of Tavorick and subsequent fight, there's a low point like The Greatest Thief. Bah.
The engine forces the "primary" character (the player-created character in single-player) to always be the talker, the special-action-doer, w/e. You can recruit a high-Charisma Paladin, but you're never able to use him as a talker; you can build other characters' Appraise skill, but you're never able to use them to barter with merchants. If you tell Neeshka (NPC thief) to sneak three screens ahead of the party, and she accidentally triggers a required dialog (with an NPC able to notice the thief without any Listen or Spot check), the PC is magically teleported to the scene, out of thin air, so he/she can be the talker in the dialog.
It's at least as stupid as it sounds. Many quests are designed around this limitation, but some are seriously compromised by this engine design (which means either bad engine design, bad quest design, or both). And besides that, it's just plain dumb; it means that only your main character's dialog skills matter even if other party members have considerable abilities in that area.
The game is also pretty buggy. If you're playing a fighter you might not notice, but many other classes are severely weakened atm. Bardsong DCs aren't receiving their proper bonus, so they're much easier to resist than they should be; Many Shot doesn't appear to work at all; the Blackguard aura weakens the party as well as enemies (uh, lol?); many spells hurt the party even when they're supposed to target only enemies. Of course, BG2 had a whole raft of such problems when it shipped, many of which Bioware never fixed (requiring the fan community to step in), so this is nothing new.
Technical stability is average. I've gotten corrupted quicksaves three or four times in over 20 hours of play, and two hard crashes. As long as I restart the game every few hours, it seems to be pretty much okay. When there are errors, tho, they're significant; losing a quicksave often means retracing 30 or 45 minutes of play.
Otherwise the game is engaging. The plot is basically linear, but it's far more interesting than NWN's OC - at least partly because all of the characters are written so much better. There's really no comparison between NWN and in NWN2 in this regard; NWN's OC was a pathetic joke when it came to characters, especially for your henchmen, but party members and many other NPCs in NWN2 are realistic, consistent, and interesting. I can't imagine romancing any of these folks, but I'm genuinely interested in at least four or five of them, and that's an achievement.