Not that poster, but I'll throw in my opinion.
Rosario + Vampire isn't amazingly original, nor is it something I'd consider frighteningly ground-breaking so far as the character design is concerned.
What makes it good is that, much like a good RPG, it doesn't do anything new, but what it does, it does well enough to keep me entertained. Yes, it is a generic Harem animu, but it has enough interesting characters and a situation desiring enough to justify me downloading it.
I agree with an above poster though. The Manga > the Anime. Pure Gonzo shit.