What surprised me most when reading the books, is how much d’Artagnan is after money. But yes, the musketeers were an unit of privileged and flamboyant men. In a way they remind me of how the hussars were said to be (same thing, womanizing assholes getting into fights, but glamorous).
Indeed! I think the main difference is that the musketeers are all nobility. I forgot if they are also nobility of sword? Meaning that their ancestors earned their privileges through feats in battle (I am not certain at all). I remember another story where a character is not high in the hierarchy, but he is said to have earned the right to ride a horse in a church.