Having rewatched this episode now after Cutie Pox is out, I am really quite blown away with how god damned good it is. Cutie Pox is nice; but this one is just really stellar, especially for a true slice-of-life story. Gorgeous animation, wonderful Rarity and Sweetie Belle acting, and some of the most dead-honest emotionally rewarding moments in the whole series.
I also just watched it in HD right up close on an iPad, and that really is such an ideal way to watch this show, I'm realizing; I've noticed this all throughout S1, but I'm only just now really giving it its full due now that I'm pulling the episodes down properly and enjoying them on weekends instead of just in stolen 22-minute chunks at work on my phone (which is how I watched pretty much the entire show up till recently).
What I mean is that this show is designed for HD. It's among the first animated shows (if not the first) to be directed in such a way that presumes an HD resolution and screen size. There will often be scenes where a dozen or more characters are on screen, or the camera is pulled way back into an establishing shot, and someone in the middle—who is so tiny you could barely even make out their face on a SD screen—is delivering lines with perfect lip sync and detailed facial animation. One of the examples I notice every time I see it is in Winter Wrap Up, when the ponies are all arguing about the right order to do everything in; the camera zooms back so you see all the pegasi in the air, AJ and Fluttershy on the ground, Twi and Spike in the foreground, and RDash hovering in the middle going MAKE UP YOUR MINDS! In any show designed with "traditional" directing techniques in mind, you'd never even show a character delivering dialogue in a composition like that; either you'd leave her completely un-animated, or you'd zoom tight in on her face while she yells the line if you want to have her emoting. With this show, the resolution allows you to see every little detail of everyone's face (including all the pegasi, with a whole range of expressions), and Dash's emoting, while still showing all kinds of other stuff going on at the same time.
There's stuff like that in Sisterhooves Social too, like all the shots of the race from up above. All the details of layout would have been completely glided over in something like PPG or Dexter's Lab; the traditional 2D art made it harder to work all those details in coherently, but also the low resolution of the final medium made it pointless. Now, though, there's a huge stage to fill with wonderful little details. Doing it all digitally must just be so amazingly freeing for these artists, for them to be able to pull it off like this—without making glaring errors or cutting any corners—on such a tight schedule and budget. I just keep being stunned over and over at the quality of the production; it's got every reason in the world to suck, but it just flat out refuses to.