Just finished the book. I have to agree with most people here that the Dany chapters were definitely the weakest, especially the early ones. The later ones got better, but the early ones were a bit of a drag. Well, the single weakest chapter was Davos' fist one, but his other chapters improved on that.
I felt that the Theon/Reek chapters were the strongest, which surprised me, as well as everything to do with the Golden Company.
Even though I think the dany chapters were definitely the weakest, I still enjoyed them and felt like it was a great book. And I strongly disagree with people calling Dany and Jon mary sue characters. For one, they have real flaws and make mistakes, and those mistakes blow up in their faces. Jon's mistakes might cost him his life.
In general, I thought the stuff happening around Meereen was simply weaker. Sure, Barriston's chapters were quite good, as well as Victarions (surprisingly). But I thought Quentyn Martell's chapters were among the weakest, and even Tyrion's chapters in Slaver's bay were definitely a step down from his usual awesomeness. I felt like his Golden Company chapters were a lot more interesting - mostly because of more interesting characters around him. The whole Penny thing was pretty dull, and its pretty obvious that she wants Tyrion to replace her brothers role/job in her life, except they would be screwing each other as well.
All I can say is that Tyrion and Dany better meet since that would be all sorts of awesome. It would instantly make Dany's chapters a whole lot more interesting and would give Tyrion a foil - someone to spark dramatic, intense, and interesting conversations. Tense drama is not what I would say would describe Tyrion's convo's with Penny and Jorah.
I am pretty shocked at what happened to Jon, but looking back at his actions it definitely makes sense. He acted like he had invincible armor on (I thought he had invincible character armor on as well - probably why I am shocked) , sending all of his friends away, making alliances with the wildings, etc, I think going South after Mance and Ramsey was simply the last straw for the people who disagreed with him. And they definitely do have a point. Well, I agree with Jon about alliances with the Wildings because that just makes sense, but going South to attack the Boltons and break your oaths? I think that was simply the last straw for people who disagreed with him on all of his other actions.
It definitely was shocking, but I don't think he is dead. Mellisandre was placed there for a reason and she has seen him in the fires. I don't think she will let him die. She either will save his life or give him back his 'life' Thoros style. I am thinking the former since having two major corpse characters would be a bit odd
As for where I would place this book, I would say its behind ASoS, but tied with ACOK in second place. AGOT follows closely behind, while AFFC lags a bit behind the others