That was a pretty great episode. I'm still a bit miffed they left out the chain (the final stroke of Tyrion's brilliance) and Sansa being forced to sing a song for the Hound. However, that's minor nitpicking. The episode worked amazingly well. Tyrion's very no-BS "St. Crispin's Day" speech, the sudden betrayal of the Kingsguard and especially the explosion were all great. Glad to see Sansa finally stand up and start showing she can take careful charge this episode.
It does show, the story work better when they limit to a few subplots (Tyrion, Joffrey and co. at the battlements, Sansa, Shae and Cersei in the Red Keep, Davos and his son) it flows much easier. I hope they keep that in mind for next season.