First and foremost the setlist is PHENOMENAL. With 28 Metallica songs and 20 other guest acts very few music rhythm games can boast such an excellent track list. Add in the Death Magnetic DLC with 10 extra tracks and it makes one meaty set of hard rockin' anthems. One difference I noticed is that the songs here are all fun to play, there were one or two moments in World Tour (the Tool songs come to mind) that were really boring to play. Also the motion capture is top notch, with really authentic animations and representations of the band. Not a huge step up from World Tour, but fans will appreciate it.
Other added bonuses include the Metallifacts videos after you complete a song, the lyrics sheets and photos and videos from the various tours. It really is a game for the fans, and any Metallica fan would be a fool to pass it up. The interface is mainly the same except this time the developers have added in the star performance meter above your score, and for the band mode it is now more clear how each member is performing.
Career mode has you as a member of band playing before Metallica at the various venues. This story is actually based on a real life band who followed Metallica round during the 80's. Progression is different from World Tour where you no longer need to complete all the songs in one show to proceed. You simply have to earn an overall number of stars from the various songs of your choice in that venue to move on.
I know this is a short review but there isn't much more to say than what's already been said in past reviews and previews. If you're a fan of Metallica and have any gaming system, buy this now! You won't regret it.