Just watched it! Both my predictions/expectations came true, FINALLY a song and the turtoise winning.
Overall, completely loved the episode!

Was grinning like a madman throughout, many funny lines, Fluttershy yay coming back, Dashie doing duhduhduhhhhhh, dozens of hilarious quick gags/set pieces, like the death course with the guillotine and shark tank...
Well, the predictability of the ending as soon as the turtoise was spotted did kinda... a bit annoy me, but it's the journey that matters, and it was a great one. The song was of course great (although songs with lots of pauses for dialogue like this work better within the episode and less as songs that you can listen to on their own, I find).
Overall, very, very good! Many faces, frames and animals are sure to become memes.
(Also, I almost embarassed myself by claiming Tank has a Hitler mustache in the last frame O_o, it's just the strap of his goggles, luckily I checked it again in higher def ^^)
"It's time to bring the PAINBOW!"
-Rainbow Dash, Friendship is Witchcraft