This week during the Service Meeting, JWs are encouraged to listen to Kingdom Melodies at home or in other "extra-theocratic" activities. Paraphrasing the Kingdom Ministry May 04, "Much of the music today reflects the worlds values." I guess that would include gospel from the "Harlot" of false religion.
However, gospel has interesting roots and fruits. It is based in African ritual music, designed for trance inducing. Witness modern gospel choirs and thier effect on audiences. It has caused a revolution in modern music and is the basis for swing, soul and rock.
One more tidbit: African JWs do not use the same songbook (with standard Western musical notation) as most of the world does. Their songs are sung without record music or instruments and the music notes are the "so-la" notation. (Think The Sound of Music, "So, a needle pulling thread...")
My personal opinion is the African culture is produces the finest music in the world, such as gospel. Its a shame JWs can't get past the glee-club mentality with "Kingdom" Songs.