Pretty Toney for me. In terms of skill set he's elite, obviously. He can make any kind of joint and it will rarely feel forced, while at the same time he puts his particular stamp on everything he does. His catalog is teflon--the five album run from Ironman through Fishscale is in contention for the best EVER, and his worst albums are perfectly fine, no real disasters.
What puts him over the top for me though, over other natural contenders for the crown, is that he's just fun in a way dudes like Nas or Cube aren't, to me. At his best he's hilarious and lively and always engaging, never afraid he might look silly or like a weirdo, because the swagger, the skills, and the music overall are always there.