I'm not usually a fan of these painful "everything that can go wrong does go wrong" chains of events, but fortunately the writers didn't play that up too much. Fluttershy needs another lesson from Iron Will, I think; up to the point where they were finally approaching the Daring Do pony's stall again, she was merely exceedingly friendly, but when she lost her bear call, I think she crossed a line. And when Dash basically traded HER away and she didn't object, she went much further beyond it still.
Actually, I'm surprised it's even permissible for a trade to involve a third party without their consent; if I'd been in Twilight's position, I would've ruled the trade unfair based on Fluttershy not being a tradeable asset alone. OTOH, maybe Twilight asked Fluttershy about this off-screen, and maybe Fluttershy said that she was OK with the whole thing. Who knows.
Rarity and AJ bickering was cute, though I'm surprised they were at it that long. At least they got something for each other in the end! I also felt that they were being exaggerated a bit too much; AJ's a very practical pony, so I'm unsure she would want a rusty old pie tin just because it bakes pies five seconds faster, and Rarity... well, she's certainly concerned about her outward appearance, but she was bordering on shallow with that brooch that she wanted despite already having an identical one, just because the other one was "vintage". But I might be overly critical there.
Pinkie was a different issue, and I think it is entirely fair to say that she was rather exaggerated. The Flim & Flam reference was clever, an unspoken hint that said volumes about her behavior; she was probably right to stop the initial trade of all of Twilight's books for a broken pen (though the way she treated that filly should've earned her a reprimand as well), but I was honestly surprised that Twilight didn't put a stop to her later antics. Perhaps Fluttershy isn't the only one who needs to (re)learn how to put her hoof down.
What else? It was quite nice to see little references to various past episodes; Power Ponies (Spike's comic book), Spike at Your Service (one of Twilight's books), etc. For that matter, Dashie's continued obsession with Daring Do is a nice bit of continuity as well; and of course I liked the fact that Twilight's princesshood is not just "on paper": she really has royal duties now (even if they're largely ceremonial), and she's recognized by others and venerated as a princess, if much to her chagrin. And furthermore, crystal ponies continue to make the occasional appearance now.
Lots of background characters again, but as usual I was too focused on the Mane Six to recognize most. I think I spotted Apple Fritter, though! And of course there was Jeff Letrotski manning the burger stand. (And speaking of stands... I was almost disappointed that the stand dedicated exclusively to Discord lamps was not manned by the spirit of chaos himself.)
The wheelchair pony (Stellar Eclipse, apparently) was pretty neat, too; I liked the wheelchair design. And the orthros (the two-headed dog) was an amusing critter — wonder if there's any relation to Cerberus there. I'm also not surprised Fluttershy of all ponies was immediately able to get him to behave; she really is exceptionally good with animals, isn't she.
So, yeah. Fun episode; not the single best one of the season, but very enjoyable. Juggling three plot strands and making everything resolve properly in 22 minutes is no easy feat, either, so despite the lack of a friendship lesson and all that, it was good.
Elsewhere: discussion in broniesaremagic. Episode follow-up on EqD. Also, some background on the wheelchair pony.