Barlow had a much more dynamic voice. He kicked ass on A Question of Heaven. The dynamics of his voice are what made that song great. Same with Dracula, I Died For You, and Damien.
http://youtube.com/watch?v=Uj5JSYiNrcc > http://youtube.com/watch?v=-o6xrSyhVhc
Edit: lol@John Schaffer's turtleneck