Been reading the NeoGaf impressions thread, it's pretty thorough with a lot of information on the nuances of the gameplay:

http://m.neogaf.com/showthread.php?t=795635&page=1

OP was incredulous about the game coming to the West, as it was very much a love it or hate it title that sold poorly in Japan. I myself don't understand how this game is coming to PS4 in the US like it ain't no thang, given how hard we had to bitch just to get Type-0. Anyone expecting gorgeous or even polished PS4 graphics will be disappointed but it's not as bad as to distract your standard JRPGer. Although some of the screens I saw looked really nice so maybe the final release will have stepped it up visually.

OP wrote this game is very hard and stressful, you can get a Game Over if a story character dies and essentially lose the last 30-40 minutes, which is painful because the combat can be slow. However, I have read the checkpoints may be retweaked for the Western version and there will be an easy mode, which might be a more viable option for most of us. There's a mechanic for chaining together turns that you have to learn, or else it will seem like the enemy is getting infinite turns. You CAN'T play this game turn by turn as you go like other SRPGs, on normal difficult you will have to plan ahead and pay attention to the turn order. Although the game has free movement and a third person view, it is described as being very different from Valkyria Chronicles and anyone expecting a spiritual successor, like I was, might want to recalibrate their expectations.

A lot of Gaffers are likening this to Demon's Souls, not necessarily because of the difficulty but because it's a niche Japanese game that looked clunky in preview videos but became a cult hit once people got their hands on it. I have a feeling it might resonate with fans of X-Com in a similar way the Souls games resonated with Western console gamers and those more used to console WRPGs. I don't know if the critical reception will reflect that, as it is anticipated that this game is sure to piss off a good many American reviewers. Still, the game has gorgeous box art so i wouldnt be surprised if some poor store browsers accidentally pick it up expecting a whimsical PS4 indie-type game.

I'm going to look for streams on the PS4 Live From PlayStation app to get a better sense of how it plays. But I'm more or less sold on it, given they don't force me to choose between the PS4 or Vita versions.