The breath control of: Its wax. What's the difference?
The flow of: Big Pun
The voice of: Xzibit
The delivery of: Busta Rhymes
The energy of: Canibus
The metaphors of: Ras Kass
The punchlines of: Chino XL
The storytelling of: Nas
The humor of: Eminem
The wit of: Ras Kass
The attitude of: Rakim
The style of: I don't know. Audio, not image. Andre 3000?
The subject matter of: Canibus (vocab), Jay-Z(mainstream appeal), 2Pac (meaningful thought), Eminem (humorous spittin 4 no reason) Ras Kass (deep concepts)