Am playing it currently. Believe me, this game fucking rocks. Its like Mafia but just that you are the cop not a criminal.
There are some uber new things in it, like reading facial expressions of witnesses, accusing them of lying based on evidence collected etc etc, which helps you in solving case.
Keep one thing in mind, there are some issues running it. I mean the game was by default capped at 30fps. Plus, its requirements are pretty much like GTA4. There are some tweaks and patches out there which removes the 30fps cap, so that you can get more fps. But those patches etc work only for default version of game which can not use DX11.
If you update the game you wont be able to use those fps limit removal patches etc, but you will be able to run it on DX11.
Personally, i would recommend not using those patches, as i have tried them. Just update your game, run it on DX11 without any fps patches, and use a commandline (like we can do in GTA4). There are many commandline for LA Noire out there, just try and see whichever suits you for some fps boost, if you need it.