Brandy was the better singer, but Monica's album was better. It was rougher, and had more of a cohesiveness in sound as well as to who Monica was. I think that edge is what made it more digestible for the hood dudes.
Brandy's album had more of a pop to it. But still she could blow, and elevated most of the songs on there. But you really have to listen to Monica's album all the way through for the full effect.
This debate used to include Age Ain't Nothin But a Number though