My main problem with the game is that you are essentially irrelevant to the story.
Your character is important to be sure, but nothing you do actually has any appreciable effect in any way beyond the direct "I missed this clue so I can't tell this person he is lying, I just have to chase him now instead."
I'm comparing it to Heavy Rain in my mind because it kind of has that feel to it, but it fails where I think Heavy Rain succeeded. At least in Heavy Rain if you failed, you either recovered in some reasonable way and gave it another shot, or your failure actually mattered, it changed something. Sure, the game was essentially the same, with 4 characters and the killer is always X, but nothing else was really set in stone. In LA Noire nothing you do matters, you could have no evidence and have no idea who it is because you asked all the wrong questions, but at the end of the day it will always be the same killer for each episode, and you will always catch him. The only time I ever actually failed something was when I accidentally drove my car onto a crime scene and contaminated everything, but it just took me to a loading screen and reset; leaving me to gather the same goddamn evidence and talk to the same goddamn witnesses. Even if I'm wrong in the Heavy Rain comparison, at least Heavy Rain left me with the illusion that what I did mattered.
Don't get me wrong, the game isn't bad. It's just that I see the potential there (the characters are amazing, not the back-stories or development, but the actual characters. They feel like real people with their mannerisms and habits.) and think that Rockstar kind of missed a great chance here
I'd recommend you at least check it out with a rent, even if you do really like the game I don't see any real replay value