I don't really like when he uses people for that purpose. But he spotlighted Kelly, and for that I'm thankful he did. She finally gets vocal recognition, and maybe this time she'll get to perform it LIVE. When she is with DC, Beyonce is normally the only one with vocals. Michelle and Kelly get the lipsyncing short end of the stick.
I've heard the song with Justin Timberlake only once, but I'm not too sure what I think about it yet. Justin has such talent, but I wasn't very fond of how high he was singing. He can have such a beautiful sexy voice--though he didn't sound strained, I would have liked to hear him sing in a lower key.