I just finished Fallout 3 (I only get to play video games on weekends, if that), so it took me forever to finish... pre-ordered FFXIII as I've always been a FF fan from the old days. When you pre-order you get this book/walkthrough, which I've read, and it looks very different with some changes I'm not sure I like, e.g.
1. For what could amount to 50% of the game, you don't build any EXP points during battles. EXP points come later on in the gameplay.
2. The main player (which you control) in your party is key. If he/she dies, the game ends. The other members of your party all do attacks based on some automatic attack system? It's very confusing.
One thing I get annoyed about with FF is each new release, they make major changes to the game, and go off in completely diff't directions. I always hate them at first, but after several hours of gameplay I usually always think "Hey, this is fucking cool. Glad they did this." So all my bitching right now will be laughed at later, I'm sure.
These guys know what they're doing, I'm sure this game will rock on all levels. The Japanese previews on YouTube, etc. look amazing, I'll be enjoying this game I'm sure.