I'm going against the current here, but I didn't think it was that well done. That was probably because reading this thread and the other during the day gave me the impression it would be something incredible, and I just thought it was rather flat. I would have loved to discover it without knowing what was coming next, but knowing how event would unfold just ruined it for me. However, Talisa's death was truly shocking, that's for sure, and as someone pointed out, Greywind's death was sad.
One little bit that I did enjoy was when Catelyn started having doubts, looked at Roose's sleeve and saw he was wearing chainmail, the look he gave her at that moment, sort of "yeah... what are you gonna do?" was good I thought.
Anyway, it was still a good episode, I just felt a bit let down by the whole Red Wedding.