I'm still only in Chapter 1, but I am absolutely in love with this game. I'm savoring every moment, trying to find every sidequest and just soak in the world. A strong, believable sense of place is hugely important to me, and Witcher 2 excels here. I'm impressed every time I start up the game.
A few months ago I'd tried to play Witcher 1 for the first time - I didn't have a capable PC until then. I got a good ways into Chapter 3, and just couldn't keep going. There were aspects I really liked, but I found so many aspects to be unrefined and unintuitive that playing became a chore for me. Still, it was totally worth playing as much as I did, if only to provide me with enough knowledge about the story and characters to make 2 more accessible and meaningful.
Back to playing. If Witcher 2 keeps up at this level of quality, it will easily be among my favorite RPGs of all time.