I've just completed this with my 6 Ranger, 1 Sorc, 10 ArcArch and 3 NW9.
First of all, I found it tough as a Ranger. When I got my +5 Arrows as part of the AA skills I was doing moderate damage, but it was nothing compared the rest of the group. Plus, as Undead are a large chunk of the game, plus after every conversation I was at the front of the line, it made things tough. As pointed out, the OC isn't Ranger friendly!
*SPOILER ALERTS*
But I enjoyed it. IMO it doesn't hold a candle to BG2 for depth - the sidequests seemed few and far between, as all the quests seemed to be part of the main quest line. The romances were laughable - I didn't have the Druid bird in my party at all, gained no inf with her, then all of a sudden, she wants me in her bed. Poorly tacked on, IMO. I didn't think the characters had much, well, character. Influence seems to do nothing and has crap all bearing on the game, with the exception of the very end. At which point, Finger of Death takes care of any traitors....!
Spells seemed lacking - why the major changes? Where's Protection from Arrows/Weapons, the mighty "Time Stop" and Contingiency? To name a few.
The ending was cliche'd and poorly executed. "Never to be seen again...or will they....?" Oh please.
But its definately an 8/10 game - and enjoyable dungeon romp, lots of fun to be had, and I enjoyed parts of the big siege on the keep. Roll on the expansions, and meanwhile, I might try playing again but as a Monk.