I think vocalists like Tamela Mann, Stephanie Mills, and Aretha had both the power and the technique that Whitney had. I like Whitney a lot but to be honest she had a great run from 1986 throuh 1998. After 98 her voice had already peaked and was on the downward slope due to her smoking. The other women I mentioned kept their voices in shape for a very long time and I take that into consideration when I evaluate things too.