Overrated: Trauma. well, that's for the Japanese... they love this song to death, yet there are other cutesy fast songs better than this which can have hand gestures to perform with. Fly High and Audience for instance.
If I have to pick an overrated song among the forum people, (Trauma isn't as popular here as in Japan :p) I would have to go with M. It's a nice song, but it's just too overrated. It ain't the best ayu song I know
Underrated: I'm having a hard time deciding between Naturally and monochrome, but in the end, I chose
Scar
Hahaha It's not even in my original choices :p I was looking at my ayu mp3s finding any song which I may be forgetting, and I came across this song. I always loved this song and it's never mentioned much at all. So sad that it's sooo underrated. So much so that it's rarely mentioned at this forum