If you can get enough out of it sounds fine, i tend to avoid songs as i usually get short of ideas to write about but i guess you can talk about the music tone, techniques in the lyrics etc..
I don't recommend songs at all unless you're able to analyse both the lyrical and musical components (i.e. tempo, tone etc) to it and even then, it has to be done well.
Songs are harder to get that really indepth analysis going, which won't impress the marker as much.
But it depends on what kind of mark you're going for... High 90's, steer clear, but mid 80's, it should be fine...