As a fan of the ace attorney games, This one has to be my favorite. I got it for christmas last year along with Justice for all and Trials & Tribulations.
There are many funny running jokes that even if you haven't played the first couple of games you can easily pick up on quickly. The characters are fun and believeable and I especially like the hintings of Apollo and Klavier having some sort of "deeper" relationship.
However: I did dislike how Apollo didn't get much character development, He's the main character and we know very little about his past. It was more focused on Phoenix (sorta). I was also disappointed that some of my favorite characters from the other games didn't make a return (Like Larry and Maya - although Maya is mentioned just not by name).
If you like games that will get you thinking, or have you shouting "OBJECTION!" into the DS mic then pick up this game for sure =D