This is an absolutely awesome addition to the BG series. Dialogues, story, quests and combat "mechanics" (the new advanced AI, for example, is GREAT) make it now my favourite, even before BG2. BG2 is bigger, and has an emotional attachment to it, but SoD feels less rushed, there are more "cross-banters" and it makes up in "depth" what it lacks in breadth. I'll never thank enough the developers for bringing me back on the Sword Coast in such an awesome way. No mod to the original games, so far, was able to give me that trill.
