She is great a singer, the songs made for her her definitely much more interesting vocally while the older songs sang by Mayu were good too but less vocally challenging because Mayu sings mostly in 3 pitches while Kihow can easily match Mayu's pitch but can easily go up or down different levels easily. You can tell she rarely loses her pitch and never seems overmatched. When you watch Mayu sings live, she struggles sometimes. Nothing wrong with it just spotting the differences. I like them both so hopefully Mayu can come back as a solo artist.