It's a matter of taste. Some people think Kuu and Namie make perfect music because it fits their taste of music. I belong to this category. These two (and Hikki) are the only ones who really still keeps me interested in J-Pop because they make good songs. I don't understand why we should try to find bad things to say when we just don't see those. Stans for these three are similar to Ayu stans who feel that Ayu makes flawless music. That's all.