I thought Doom 3 was shite too. Wasn't that ID? All style over substance.
Also, I was too scared to play it.
I bought this last week for the Xbox my missus got me for Christmas. I'm amazed, it's a beautiful, intense and terrifying game.
The ending sucks ass. Other than that, good game.
I've read that the way to play LA Noire is to turn off all the hint systems that're checked on by default, only then do you get the real challenging and absorbing experience that the game was designed to be. The hints leading you to clues and evidence whilst searching the crime scenes I'm talking about; play it without any of those and it stays fresh and maintains its realism.
Did you play that way?