Best:
The perfect pear: Definitely one of the best episodes in the entire series. It just goes to show that MLP is still wanting to take risks and pull it off nicely. The questions the fans been questioned a lot had finally been answered and the results were great. An episode people can enjoy and relate to.
Parental Guidance: Funny, yet heartwarming. It goes to show that even the egotistical person can be reasonable. Dash's parents are all likable and overall nice parents. You can tell why they are perfect for each other. Dash's anger can be reasonable and Scoot's breakdown is also reasonable too. You can see both sides of the argument and how each of them differ.
A Royal Problem: I never really considered it to be the best of the series, since there're parts that rub me the wrong way, but the way the episode handled it is really satisfying. Celestia's other side of her emotions are really entertaining plus some good humor into it, pretty heartwarming scene at the climax there for the sisters and Starlight being overpowered isn't such a bad idea (she's not a mary sue).
Honorable mentions:
Shadow play
Once upon a Zeppelin
Fame and misfortune
Uncommon bond
Worst:
Secrets and Pies: Never in my life have I felt so much negative emotions in one sitting. It's trying to be Party of one but it never gets it right. The craziness of Pinkie Pie feels unnerving and sad seeing Pinkie is desperate to make Dash eat her pies. Dash's dumbness is not even balance here. Sure, she threw her Pies through donations, but throwing in the trash at the beginning just leave in to more suspicion on her end. All this wouldn't have happened if Dash could've ended it when she saw Pinkie's despair and over the top plans.
Daring Done?: It's kinda boring, to be honest. Been there, done that. The villain was obvious. The only good thing I could say is the legend. That was the only interesting stuff.
Hard to say anything: I don't have anything to hate, honestly. It's a guilty pleasure of mine. Though I could say the quality of it is really bad and not the best in the series.
Dishonorable mentions:
Triple treat
To change a changeling
Honest Apple