All I can say is wow.
Although the game starts of fairly slow, pace does pick up fast once you are past the tutorial cases and you are free to carry out cases at your own will, It's not a fast paced game at all, it requires thinking, and thats what I like, It's similar to the Phoenix Wright series, you need to be able to detect contradictions, lies and truths.
Team Bondi and Rockstar have made an unusual approach, using a new way to record facial animation, many cameras are used around an actors face to produce an exact replica in the game world, you're use of psychology is put to the test as you watch carefully peoples reactions to your questions to detect if they are lying - just like in real interrogations.
It's definitely a unique game, do not be mistaken by comparing it to Grand Theft Auto or the recent 'Red Dead Redemption, there is shooting in the game, but it does not occur often (And you can't massacre people on the streets!)
I love it so far, and I can't wait to get back to it!