Yes, Rarity does have a great VA. I love the way Rarity stresses certain words ("My DESTINY!", "YES"!). The fact that she is hilariously OCD makes her funnier.
Out of the background/minor ponies, I'd like to see more of Big Mac and Braeburn. Braeburn made me laugh a few times, and a few more male characters should make the show funnier (especially if boy-crazy Rarity and jealous!Spike are involved). Derpy Hooves and Zecora are also cool.
What I love about MLP:FiM is that all the mane characters have a mental issue and could be batshit crazy: Rarity has OCD, Pinkie Pie is schizophrenic, Fluttershy has deep-seated rage issues, Applejack works too hard, and Rainbow Dash has the chronic need to be validated. Twilight Sparkle is the only ordinary one, and she's at the beck and call of Trollestia. XD
Personally, I like Harry Potter and Avatar: the Last Airbender as fandoms. We already share some literary loves (Artemis Fowl, Poe, etc.) I want to know about the others. xD