Rollercoaster is indeed being featured by Miguel and apparently he doesn't have a big input on the song. It's one of her most electronic pop songs with 80s/90s pop and house influence. The label is still insecure of which song to release as the lead single cause the album is full with pop candy songs. Oh and the track sounds a bit like a combination of the "Sasha Fierce" and "4" era.
Only a select few have heard the song. And apparently the person who leaked the info is going to get in some serious trouble

And that melanie girl that said she heard the song on radio must be false. They aren't allowed to play those two tracks they send out yet. We MIGHT hear the song in the second/third week of January.
My Source: The same guy who "leaked" previous Kelly songs, and one of the first to hint about her greatest hits album. He's a intern.