Yeah, it's pretty sweet. Here it is in action if you wanna see it:

Final Fantasy XIII Battle system gameplay - YouTube

One thing that bugs some people is that you only control the party leader in battle. AI is good for the most part. My only complaint is that it can get kind of wonky with Esuna. If your party leader dies, it's game over. However, you can restart just before the encounter rather than your last save point.

EDIT:

Oh, one thing that I thought was pretty neat. In some battles there are opposing monster groups. In that video the wolfy monster things were actually fighting the Behemoth before that battle started. If you can sneak up on those encounters and get a pre-emptive strike, they'll usually continue to attack each other rather than your party. If you defeat one group, the other group will start attacking your party. You can whittle down two really tough minibosses without getting a scratch on your party if you manipulate things just right!