I'm 13 hours in at the moment, and I'm having a blast. I admit it is somewhat annoying not to be able to choose my party, and I haven't even gotten to play as fang yet at all, but having everyone split up really adds to the story in my opinion. Yeah, they all got turned into l'cie, but that doesn't magically make them all have a fantastic friendship right off the bat. They've got to figure things out, decide what they need to do and why.
Lightning (so far) is shaping up to be my favorite main character of any FF game. I can completely understand her actions and motivation. Although I hated Hope and Vanille at first, they are starting to grow on me. Hope looks like he is about to turn into a mini-Lightning soon, and I'm just now starting to see through cracks in Vanille's "I'm always really really ridiculously happy" facade. All her orgasms are still annoying though.
Snow has some stupid moments, but again, I can understand why he is acting the way he is. Too many past characters have done things seemingly because they just have to for the story to progress, but now it's like everyone's actions actually make sense. Although I am still trying to figure out what's going on with Fang and Cid.
Oh, and on that note. I remember reading reviews where people said they were always confused about what was going on. That's another reason I'm enjoying this, because the game is actually conducive to thought. You have to make an effort to understand what is going on rather than something like "bad guy kidnapped princess, rescue princess GO GO!".
The battle system is quite nice, in my opinion. I see people complain about the whole auto-battle thing, but you don't even have to use it. Paradigm shifts are interesting, and to be honest it is a nice change from having to worry about mana and a dedicated healer/mage in the party that can't do anything else. I see lots of people complaining that the game plays itself for you, but so far it actually requires plenty of player input. FF 12 was the game that played itself for you (lol gambits).
In regards to the linearity, I have no problem with it. If I want to play an open-game with the focus not on the main story, I'll play Morrowind or Oblivion (although I did like the story in those games too to be honest

).
TL;DR - I like it as of 13 hours in. While that may change, I doubt it.