Where to start.
Answer (and links) after the break.
Rarity’s a good pony. Sometimes I get the feeling she hasn’t really grown up properly; she doesn’t really seem to have the kind of restraint you’d expect of a pony of her standing and occupation. I think she just needs more time to grow accustom to responsibility beyond her own. But either way, when the cards are down she’s always out to help everypony involved, even to a sacrificial degree.
Rainbow Dash has always been cool with me. I don’t think it’s fair to call somepony out just because their interests are stereotypical. For that matter, when those interests are involved, she’s willing to spearhead a project like she did with that waterspout thing. Maybe her intentions weren’t the best, but if Ponyville’s pegasus had managed to break that record it would have meant a sizable boost in government funding for Ponyville’s weather division.
Pinkie Pie is Pinkie Pie. The first impression you get of her is pretty much who she is. But from other similar ponies I used to know, I’m also well aware how taxing extended one-on-one time with somepony who never shifts down can be. I don’t think anypony treats her like an idiot, but I wouldn’t presume to know for certain. Out of the six, I’ve spent the least time with her.
Applejack is one of the nicest ponies I ever met. She’s willing to help just about anypony with just about anything she’s capable of. If Sweet Apple Acres isn’t producing the kind of income it should, it’s probably because of how much they practically, and sometimes literally, give away. I’ve spent plenty of time with her and she’s an absolute gem. Out of everypony in Ponyville I can’t believe somepony would have anything bad to say about her!
Twilight isn’t always the easiest to read socially, but she isn’t trying to be overbearing. She just genuinely cares about the books and wants to make sure they’re properly taken care of. She was the same way in Canterlot. As for Spike, this is a classic case of somepony trying to stir some trouble without even knowing what they’re talking about. Just as Twilight is the Princess’s magic apprentice, Spike is Twilight’s scholarly apprentice. They aren’t siblings; they aren’t family. They’re friends, but at the end of the day Spike is there to work and learn.
Fluttershy’s different. I didn’t like her at first. I didn’t even want to like her. She struck me as some social coward too afraid to live in society. Not because she couldn’t; I’d seen her in Ponyville before. She just choose to hide away and make friends with animals because it was easier or something. But I was wrong. Before she closed her tumblr I saw that she was very intelligent, creative, clever, extremely patient, even a little tongue-in-cheek. She had brilliant comedic timing and she wasn’t all, “Oh, Um, That is, If that’s alright with you.” At this point, I think the only problem she really has is speaking face-to-face with ponies impromptu. I even used some of her artwork to put together a fan video for her (mind language warning).
As for her “pets,” they’re trained to preform at events, which gives her the money to take care of them. In a way they are fending for themselves, the same way everypony else in our society does, by working.
At the end of the day, they all make good friends. And if you require more than that in any given relationship, I don’t know what to tell you.