Hey Dubai fox, here's some thoughts (though i don't make a living from it) :
Does it offer the audience something to remember after watching the commercial?
Does it get repetitive and annoying making you want to turn to a different channel each time it's aired?
Upon hearing the music or sting again on its own, would it trigger an image of the product in the observers mind?
Does it suit the product advertised? Was the music made more serious for an expensive luxury car or did they chose a piece more appealing to young people?
Just my 2 cents