And you should wait for the Enhanced Edition of the Witcher if you decide on getting it.
I played it through. The game was good (but not as good as a lot of people said). The story was from mediocre to good-ish with some really nice touches here and there, the C&C was nice, the maturity of the setting wasn't really there, the visuals were stunning, the environments gorgeous, the atmosphere captivating, but it's greater problem was the gameplay. And that's 'cause a lot of times the whole experience seemed just like a chore.
I'm not really sure if I can recommend it. I mean, I kinda liked it but I'm a huge sucker for dark fantasy and still it managed to make me say all that stuff about it. If you find the dark fantasy setting to your liking and don't mind sassy in-game comments about the game's moral ambiguity (probably try not to take the RPG-watch review about the game's story too seriously as well) then it would be a nice experience, I think. Anyway, I sometimes think I'm overly too critical with this game for some reason. Maybe I set my expectations too high. Still, you asked about opinions and that's mine. Maybe people that liked the game can give you an idea of what they thought of it.
Psychonauts is like one of the awesomest games in the universe or something, btw.