The Season 3 premier of Friendship is Magic was sheer brilliance. Everything from the plot to the characters was pulled off to perfection.
The character progression of Spike was a high point personally for me. When they interacted with the Fear Door, it really felt heartwarming to see Twilight and Spike truly love each other, and moreso to see Spike take on the role of eventual protagonist for that episode. He's deserved it after the years of being the right-hand dragon.
Aside from the very plot-device seeming villain, everything about this episode was cuddly overall. Would HEAVILY recommend a watch :3
EDIT: Here's the double-bill in 1080p