Voice and music in this song sound fine to me. Of course I do not understand the words.
I listen to many world music songs that I don't understand words... But still like them. I listen to many Arabic tunes, Oriental tunes, and other. And yes, Greek tunes are some that I certainly enjoyed. My BFF was stationed in Greece in Navy. He turned me on to some good tunes from there.
I too, listen to songs I can't understand. I don't feel like it stops me from enjoying the music. Eurovision is a great place where one can hear many different types of music, as well as many different languages (although there has been a decrease in quality over the last few years). Do you happen to remember any of the Greek songs you used to listen to?