I've never gotten very far in either the Penumbra or Amnesia series of games, not because they weren't any good (quite the contrary) but because they were far too terrifying to play.
This game was actually shopped out to another studio so hopefully it is still on par with what Frictional would have released. Dear Esther was a beautifully made "game" so I have high hopes.
I played Amnesia a bit but didn't like it very much. Movement was really awkward and it felt too much like the player was arbitrarily limited in his abilities to make you feel vulnerable. I didn't feel vulnerable, just annoyed and tired by the fact that so much as blinking his eyes made the character go crazy because he thought lights turned off.
Also, people who complained about Doom 3 being too dark should never, ever play Amnesia.
Put in about 30 minutes so far and while it definitely has a very scary atmosphere, I'm quickly learning that there is no bite behind all the bark and growing less uneasy from all the random noise, voices and shaking.
The voice acting is good so far but the notes aren't as good as the first games. The biggest annoyance for me so far is that the lantern seems to be unlimited, there is no inventory, and the world is far less interact-able. Hopefully it picks up a little more gameplay depth.