Just heard it!

Wow. I was afraid it would be hyped to the point of disappointment but it lives up to everything I hoped it would. Mariah and Whitney are both incredible and uncomparable. Their voices just melt into each other's on this song. The powerful, climactic ending will blow you away. I had doubts about it being on top for very long since there will be so many other artists with releases this season (Alanis Morissete, Garth Brooks, Celine Dion), but now I believe.