I love that Rarjack and Raridash are both very similar and very different at the same time.
The similarities are obvious. Rarity is a classy femme that cares about make-up and fashion and looking nice and pretty and impressing aristocrats. Rainbow and AJ are both very messy butches and I have the impression that they don't shower every day and would never dream of lying about who they are to impress Canterlot snobs or even wearing a pretty dress on a Tuesday.
But the differences are interesting. Cause AJ is a pretty down to earth pony. Over the course of the show, Rainbow and Rare have Dreams and Ambitions that they want to accomplish; being a famous flyer and being a famous designer. AJ is exactly at the same place at the beginning of the show as she is at the end, her Ambition is to take care of her farm and her family. She obviously grows as a person (er, pony) but careerwise she's always been where she wanted to be.
And it's kinda interesting that Dash and Rare are both Big Dreamers while AJ is very satisfied with her life as it is, it's a fun contrast.
AJ is also not very loud in her presentation. By which I mean she's the least dramatic of the 3. Rarity's a drama queen prone to fainting on a couch at any moment, Rainbow has been known to freak out over small stuff herself. Applejack is pretty chill in comparison.
So you got these two bombastic, loud, passionate personalities and then you have the stubborn, honest, dependable voice of reason.
So yeah, Appleraridash for the win. They all have 4 hooves. Rarity's harem of mascs.
