Considering the fact that they have different personalities, still I think they get along just fine. Applejack, Twilight Sparkle, Fluttershy, Pinkie Pie, Rarity and Rainbow Dash are all best friends. I know that in some episodes they find each other really hard to cooperate like Applejack and Rainbow Dash, Rarity and Applejack but they soon learnt their lesson at the end of the episode.Its just one of those times people think its impossible to actually think you'll turn out to be the bestest of friends when the both of you are completely different.