Man, oh man, was this episode great! My favorite since "Lesson Zero."
Derpy speaking was a wonderful surprise and was quite hilarious. But, Pinkie Pie truly stole the show in this episode. Her being the "big gun" (the awesome act-break smash-cuts were a nice touch) to get AJ to talk was hilarious, but when AJ broke the Pinkie Promise, I was rolling from her reaction.
Also, "Rarity, catch me!" was really funny, as well as the ending.
The episode had a lot of energy and was briskly paced, packed with wonderful jokes, references, great music, and was just enjoyable from start to finish. It's episodes like this that make me love this show.
A