It was a sweet episode, well-written, with great characterizations and interactions between the characters; it never felt rushed, but it never dragged on needlessly either, it had a nice song, and it brought tears to my eyes (twice!) just like it did to Twilight's. It was fun, it was entertaining, it was silly (without being over-the-top zany), and most importantly it was touching: when Twilight and Spike visited the remains of Golden Oaks Library and also when Twilight found what her friends had done in the castle's throne room.
I really liked the plot. I enjoy stories that are part of a larger overarching narrative, and I have a weak spot for slice-of-life, so Twilight finding it difficult to adjust to her new home vibed with me on several levels. It makes a lot of sense after everything that previously happened in the first four seasons, and seeing how difficult it was for her reinforced her as a likable, relatable character: alicorn princess or not, she's still the same Twilight we've grown to love.
Everyone else was equally well-written; Pinkie's bubbly exuberance, Dash's healthy narcissism ("I prefer to think of them as everypony's trophies but with my name permanently etched onto them"), AJ's and Rarity's occasional friction, it all felt spot-on. Fluttershy, meanwhile, displayed how she's changed and grown over the seasons; I don't think she would've been able to give that snarky reply to Pinkie a few seasons ago.
But I'd like to single out Spike as the all-too-easily-underappreciated one in this episode. He has always had a tendency to speak his mind and call out the white elephant in the room, and did so brilliantly here on several occasions; at the same time he's also helpful and caring to a fault, and this episode demonstrates again why he's one of the best friends and number one assistants any pony could ask for.
And then there were the spa ponies, a perennial favorite of mine; I think this episode marked the first time that either of them – Aloe, in this case – had a speaking role, too. Same for Bulk Biceps: not that he hasn't spoken before, but I enjoyed seeing him being given a few more words than just his signature phrase. And he WOULD be a natural at moonlighting as a masseur — poor Spike, though.
Other bits and pieces: Pinkie's hidden confetti cannons that went off at the most inopportune (yet fitting) moments were amusing. I'd sure like to try a seven-layer what's-that-flavor mystery surprise. Dashie getting excited when cider was mentioned was awfully cute. And she hasn't just got Wonderbolts and Daring Do posters, she also has a Spitfire figurine — gotta teach the target audience that merch is good, eh? :) The Mane Six continue to be quite expressive; Pinkie borrowed that "barking mad" face from Screwloose, but others had better faces yet. AJ bent her leg in a weird manner at least once, though I don't know enough about horse anatomy to say whether that was unrealistic or not. This is the second SxE03 episode in a row that's about a castle now. And Twilight's bedroom has stuffed animals in it, awww. :)
All in all, an outstanding debut for both Joanna Lewis and Kristine Songco, and easily the best episode of the season so far. Given it's only the third, that may not sound like much, but I expect it may well remain one of the top episodes of S5 — though if the rest of the season's good enough to outdo it still, I sure won't complain!
Elsewhere: discussion in broniesaremagic. Episode follow-up on EqD. Review by drhoz.