Twista's rapidfire style works quite effectively with R&B. Whether it be on his biggest single, "Slow Jamz", or his many features on other artists songs (including a guest spot on Jeremih's Late Nights), the rapper shows a greatly effective contrast with sung vocals.
Twista's upcoming album, Dark Horse, is due out August 12th. The rapper revealed both the cover art and full tracklist just last week. You can take a look at that here.