Good but dull.
All I can say is, it's simply boring. It's not a game I could really get into. I've had it for over two years now, and I've yet to finish it. It's mildly interesting, but it feels like a chore to actually play it. I cannot put my finger on why this is, but some factor in the playing of the game simply leaves me uninterested.
It's very difficult to react badly to a game that has no flaws. Many complaints surrounding The Witcher deal with its bugs, but I've never encountered one. For a game with excellent everything and zero flaws, it's just... uninteresting.