I think you should definitely have the other half of this book handy when you finish because, in my opinion, the ending comes very suddenly. And, even though I hardly thing of Martin as someone who ties of all stories by the end, there is much stronger feeling of this volume being unfinished and the stories indiscernible. Writing this a few days after finishing it, I can entirely remember what happened since everything felt unfinished. I guess in some ways I don't understand why they felt the need to split this book in two- besides its ungodly length.
One of the more interesting things, for me, is Brienne and Jamie. I think they are both different one another: the only similarity being that they have this intense idea of loyalty, though the loyalties themselves are very much different. I have the sneaking suspicion that these two will have some sort of romance- even if its just a singular, unrequited one. And I'm not saying it would just be on Brienne's part, which is the conclusion I imagine people would jump to. I think it is just as likely that Jaime would like her and be not liked back. Okay, the former is more likely, but I'm learning never to expect things with Martin: it only leads to disappointment.
The only other thing I noticed (and the biggest giveaway this is part one of two) is that there isn't a great deal of death! If you've read Martin or are aware of the story, you'll know what I mean by that. He's almost blood-thirsty the way he will kill some characters who we've come to love so much. He says its purposeful: that by caring about a character we'll care about their death and it should bring home the horror of war. But to read like that- knowing that he could kill anyone at any time- can be soul-destroying at sometimes.
I'm at the point now where I know not to expect a happy ending to this entire story and I honestly expect most of the point-of-view characters to be dead by the very end, though it seems unlikely. The first part of this isn't happy by any stretch of imagination and if there haven't been any notable deaths, I expect part two to be quite a blood bath.