Just finished book 5. Good, although I was pretty bored with Theon/Ramsay. Seems like they had to add Ramsay as soon as they offed Joff.
Bringing back Gregor is bullshit. I know that Martin doesn't want these stories to be classic good v. evil affairs, but I think that evil wins out almost a bit too much. It's almost predictable: If it isn't express stated that the person is dead, they're alive.
But really this is the most complicated series I've ever read. Overall I've loved it, though there are too many characters for me to keep track. Family names can also be very similar. Tyrell, Tarly, etc.
On some of the characters:
Tyrion might be my favorite character.
If Jon is actually dead, which I doubt, he almost deserved it for how moronic he acted.
And oh yeah, Brienne is fucking boring.
Cersei is like a freaking cartoon villain with how invincible she is.
Jaime is sort of likeable, but his character only changed because he couldn't be as alpha as before his hand was chopped off and was pissed because Cersei cheated on him. Still not completely likeable.
Arya is murky. I missed how she killed the man by giving him the coin.
Robb was boring, as was Catelyn.
Sansa is going to take the throne from Cersei/Tommen, obviously.
I'm guessing Bran takes over one of the dragons before the books are over.
Davos and Barristan are awesome. True loyalty.
No idea where they're going with Rickon.