Played 2nd edition. Good game. Second edition in particular has a lot of good writing, especially in the scenarios. I love Call of Cthulhu, but one of the problems with that game is that the horrors of it tend not to be particularly sinister nor personal. You are facing ammoral monstrousities that are morally the functional equivalents of forest fires, asteroid impacts, and local supernovas. They can be terrifying, even horrifying, but there is nothing particularly personal about them. You just happen to live in an impersonal world filled with devastating chaos. But in Chill, the monsters are smaller and more intimate. They aren't merely destructive or unfathomably alien, but they hate you, want to corrupt you, and eventually eat you. It's a different scare than CoC, but its often equally or even more effective.
Lethality depends on how gritty you are in character creation. Depending on the points you supply the players relative to the challenges you assign them, you can have characters that will almost certainly die in a horrible way - the extras in a slasher movie - to Hollywood action heroes who can survive from session to session.