I don't know. I think ASOS is the best book so far, but I really don't get a lot of the criticism aimed at AFFC and ADWD. If there hadn't been such a real world gap in their releases I, like previous posters, don't think there would have been as much complaining. They ARE paced different, but that's not bad. They have different goals in mind. I think they are all about worldbuilding, especially ADWD. We see MUCH more of that area of the world than we ever have before and much of it needs setup. I for one found it fascinating.
I also find it interesting when people complain about so much time being spent on "unimportant" or "minor" plotlines. We have not seen how this story ends. It hasn't been written yet. As such, we have NO idea whatsoever what may turn out to be important and what may not. I think such judgements have to wait until the saga is concluded. Hell, the whole concept of the ring seems kind of superfluous in The Hobbit, but we couldn't have The Lord of the Rings without it.
And I REALLY don't get the criticism that "nothing happens" in AFFC. There's a lot of stuff going on there.