Other Gospel choirs - Thomas Whitfield, known as "The Maestro" in the gospel community. This guy was top notch! Actually did some work with Aretha Franklin - one of his best works was Alive and Satisfied (songs of note "Only A Look", "Nothing But the Blood", "Overture of Worship", and "In Case You've Forgotten").
James Hall is another person that has great gospel choir music!!!! His work on "The Blood" was terrific!!!!
A lot of audiophiles tend to like smaller scaled gospel such as what we call Quartet music. Dixie Hummingbirds, Fairfield Four, Blind Boys of Alabama, ect. These are indeed Gospel greats, however the sub-genres of gospel are just as complex as other types of music.