This is week two (or maybe three) of playing The Witcher, and I'm still on Chapter II. So far I haven't completely lost interest in the game (and after spending this much time and not getting very far, I doubt I'll stop playing if I do), and I think I'm nearing Chapter III, where I've heard things pick up. I've discovered that one bad part about this game is the whole night and day thing. With as many quests as you get, it's hard to keep track of which ones you can do/finish at what time of day. This is especially bad in Chapter II, because some quests require you to be in the Swamp while others require you to be in Vizima. It's a little annoying going back and forth all the time.
I'm still having fun, though, so that's a plus.