My issue with this episode lies here; Rarity, Applejack, and Pinkie Pie feel like they've never met. Instead of sitting down, discussing what happened, forgiving the person that was "responsible" and moving on, they refuse to talk to each other and distance themselves from one another. To the point where Twilight has to lie to them about a friendship emergency to get them to even see each other. Not sure about you, but those are definitely not the girls I know.
Seeing the different pony's views and stories of what happened was interesting, but it falls under much the same problem. It's so strange, almost surreal to see them hating each other so much. This might've worked as an earlier episode. But this is season 6! They've been close friends for 6 years (or however long 6 seasons is in the show).
The ending was pretty lousy too. I hate endings that you can't possibly guess, no matter how hard you think about it!
Overall, I give this episode 5/10. Not the worst episode, but definitely one I'll be avoiding in the future.