So, I don't know if this will sound weird or what, and I don't know if anypony else picks up on little details like this, but I love the way Rainbow's voice sometimes sort of breaks when she sings a word starting with the letter "H." Let me clarify. Listen to her short solo in "A True, True Friend." Listen to her line, "Applejack needs your help; she's trying hard doin what she can." Specifically, listen to the way she says "help," and "hard." Her voice sort of breaks/cracks a little, sort of like the sound she makes when she laughs. I absolutely love that. It's so endearing. It's not typically a feature you would think of as good when it comes to singing, but it gives her such a unique flair. She really has such a surprisingly beautiful singing voice. She needs more singing time in the show.