I choose Killer Bee because he has the 8 Tails and Samehada. His speed can be on par with the Raikage (A). For Danzou only has 10 tries to take him out with Izanagi which I doubt he will be able to use for to long without wasting chakra. Danzou might have a summoning but with Killer Bee 8 Tails transformation the summoning want do much. Danzou also has Shisui which he could only use for a day and mention he have to look at Killer Bee directly in eye to use the technique. Killer Bee can easliy counter that without looking at Danzou in the eye.