Vocally the Dream and Mariah harmonise well, as both singers have a smooth, airy quality to their midrange voices.
Mariah is up to her usual tricks, blending her higher and lower vocals for her verse, but its nice to hear her lower range being utilized. Her vocals, overall, have a more relaxed and organic feel than I have heard before; almost as if shes not trying so hard to make this a technical performance.
Point in case is the scratchy texture Mariah's belts are graced with when shes sings the "know" in "they don't know" at 3.24. I, for one enjoy the rougher texture to Mariah's voice but I'm sure this will have people who like to bemoan about Mariah's changeable voice citing it as evidence of her vocal decline.
Hopefully an insight into Mariah and Dreams' songs for her new album that he has been refering to as 'MC3'.
OVERALL: Kinda average untill Mariah starts singing
Mariahs High Note from "My Love": E6-F6
Update: The album was actually released as The memoires of an Imperfect Angel (read the review here).