it's interesting to see ayu collaborating with younger/newer artists and trying out new stuff. I'm actually not a big fan of naoya's singing style either. I don't know if this sounds right, but his voice is not "man-ly" enough for me. >.< but tbh, any new ayu songs will work for me right now.
It surprises me how JUNO also sings in mandarin. I'm quite an avid cpop listener, and I had never heard of him.