I enjoyed seeing Granny Smith's flashback; I like seeing her as a younger pony, and there's a lot more to her character than being the stereotypical "quaint old gal". Unlike in Family Appreciation Day, where she was fairly weird, she's actually more or less a normal pony here. (And "Fiddlesticks" is a great exclamation. I still think it's a shame they couldn't go with that name for Fiddlesticks herself!)
I also honestly never expected to see the Flim Flam brothers make a return, but their new job as snake oil peddlers really fits them exceedingly well. And it got us another great song. :) (And isn't it funny how the brothers managed to produce something quite palatable now, despite failing when they actively tried to in The Super Speedy Cider Squeezy 6000?)
The conundrum AJ found herself in in this episode was interesting, complex and surprisingly subtle. Is honesty always the best policy? For that matter, is openness, and are the two the same thing? One wonders how everything would've played out if things hadn't gotten out of hand as much, and one also wonders what Applejack's reaction would've been if Granny Smith had not taken the news well and returned, crestfallen, to her former aquaphobic self.
But fortunately, everything worked out well for everypony.
Quite a few background ponies, including our resident attention horse, Lyra. (I still found myself unable to name many of the others, alas.) The other Mane Six were completely absent, as were the rest of the CMC, but AJ really shone. Also, we got to see Big Mac with a wet mane.
Random observations: ponies have wheelchairs, and they work in much the same way that dog wheelchairs do. AJ writes using her mouth (obviously), and she's good at it.
I don't want to write a novel again, so I'll wrap this up here and say it again: very enjoyable episode. 10/10, would watch again.
Elsewhere: discussion in broniesaremagic. Episode follow-up on EqD.