Just to let everybody know, this is not the last one.  I don't even think the next series is a prequel because then Luke would be around three years old, but let me get on with the actual review.

This is definitely the best one yet.  It has the most puzzles, best story, more variety of puzzles, best lineup of characters, etc, etc.

First off, I don't want to say anything about the story because that will just spoil it.  Lets just say its one of the best of any game I've played recently, with tons of plot twists, and an ending that I actually thought was really sad.

Next are the puzzles which are basically the same as the other games but are always fun and challenging, and are great to tell to your friends and watch there blank expression as they try to figure it out.

The Professor Layton series has always been a favorite of mine because of all of what I just said, but also a lot because of the voice acting, which in this one is just as good, if not better, than the others, and there is a LOT more.  Every character has a great voice you cant help but like, and that you wish would talk for every line in the game.

Overall I 100% recommend this to anyone who hasn't already bought it, but you should really play the others first to enjoy it like it was meant to be.