They all bring something to the table. Clearly, the most talented and well-rounded (writing, producting, etc) of this group is Mariah Carey whose historical musical resume will be long and fruitful enjoyed by all ages. Then Whitney, who should have been close to an equal level of success with MC had she not made some seriously bad life choices, detrimental to her career and her voice. Beyonce is more of a pop singer than R&B and an entertainer. Maybe she can transition into a Tina Turner-type for the long haul, although her voice is not as rich as Tina's. Brandy has a sweet, quiet voice, kinda like Janet Jackson. Her choice of songs will determine if we're still talking about her in her 40's and on.