I've been playing this for a few hours now and it's incredible. I didn't even know this game existed until a couple weeks back when I purchased it on the art style alone.
To say that the developers completely nailed the art in this game would be an understatement. Everything fits so well, from the characters, both on and off the battlefield, to the beautiful animations, the environments scrolling past you, the menus, the text. Everything is exactly as it should be on the visual front.
The battles, so far, are somewhat simplistic. That's not to say they are bad, but people looking for a really complex strategy game might not be fulfilled by this. Each battle takes place on a flat surface with no obstacles or hazards to get in the way (at the point i'm at anyway). Each character has 1 ability which you can activate using your willpower. You can upgrade your units in a straightforward manner like giving them +1 strength, +1 armor, etc. The battles really bring nothing new to the genre, but they also don't need to. I have yet to find myself frustrated or bored with the combat which is more than I can say for many games.
Every choice you make in this game matters. I have stared at the screen on several occasions trying to carefully choose my next action. Some choices I've made have had immediate effects and some I can tell are just going to come back to bite me in the ass. I'm looking forward to continuing the game and seeing the consequences of my actions (or non-actions).
The story, or more specifically, the characters in the story, are a bit confusing at first. It really helps to read the brief character bios on their stat pages if you are feeling lost. I wish they would have a summary of what happened so far, including the personal choices you've made during the game.
Also, the lack of subtitles is disappointing. My speakers are terrible and the audio that plays during certain cutscenes just had me kinda sorta knowing what the person was saying.
I really hope this game does well for them. They've created something pretty spectacular here.