It's also refreshing to have something to go back to, which has not a pg-13 rating or sth. similar.
See this: http://www.esrb.org/ratings/synopsis.jsp?Certificate=31097
I can't stand it when mature topics are marketed to children.
The developers weren't afraid to change the core of the gameplay of its predecessor. Still, this is again based on the book-series but plays after them. Thus the environments are already much more fleshed out than in a media. It is said, that Witcher 2 doesn't spoil the books.
The graphics are good and a few very harsh difficulty levels also cater to the people who are looking for a challenge. You don't find permadeath often these days.
The bad things: the environment is not as open as it looks. That was done out of necessity. The different plots touch each other once a while. A permanent ability to visit all other locations would require too much dynamic in story-telling. The inventory is small and Geralt is not always listening to your commands and decides get his sword out. Targetting enemies in a crowd can be problematic because it is working based on your view.