The short version: Meh.
The long version: First of all I am happy that they decided to go with a less political storyline, that's what really killed FFXII for me.
The battle system is chaotic, but useable. While replenishing your troops mid battle is sometimes cumbersome and slow, selecting specific troops or units while fighting is a breeze. Picking a set of 5 espers to bring into battle is a nice bit of customization, but I would really like to be able to set up default battle groups. It's irritating when I have two characters that are flying units, and two flying espers of different elements, then at the start of a mission, the game defaults to giving each character one esper of each element. But other than that, the default groups are spot on.
The gambit system is really simplified in this game, each character gets abilities through leveling up (and support abilities from gear) you can select one of these abilities as that character's gambit. Basically, that means that whenever the timer is up, that character will use that ability.
Haven't gotten very far into the game, so I don't have any opinion on the Forge, Quickenings, or beefing up your espers.
The game is entertaining and a solid RTS game, but it's just a little bit too much RT and not enough S.