Alan, thanks for creating this space. Really great episode. There are no spoilers, but there are book to TV comparisons.
Brienne was better than I expected. She was one of those characters who I could not imagine anyone properly playing. Somehow they managed to find an actress both tall enough, built enough, and yet she still has that innocent quality that makes the character so great.
Margaery is definitely different than in the books in that she is more forthcoming, especially about her knowledge of Loras and Renly's relationship. In the books she was just this very pretty, very polite character who everyone seemed to love, but that was all based on other characters' opinion of her.
The scene with Theon and Balon was not in the books, as far as I recall, but was one of my favorite Theon scenes in the series.
Even if I didn't know Yoren was going to die, any time a characters spends that much time opening up about himself in a TV show generally means he's going to get killed off. Pretty sad how all the strong, male figures in Arya's life keep getting taken away from her or killed.
The episode was so good I didn't even notice the lack of Robb Stark, Stannis, and Dany storylines.