Very cute! Ema Toyama is really a genius mangaka. Pixie Pop was the first manga of hers I read. Mayu is a really loveable character.
It got me hooked on her stuff! Mamacolle was also great with a very similar cute heroine. However, though I enjoy Pixie Pop, I think the author did a much better job with I Am Here and Do XX To Me. The storylines and art she does are always good, but those last two I mentioned have much better developed characters.