Cain is a different Animal then DC. SURE, they both have a similar style but they have entirely different bodies and attributes, Cain is a much better striker and has way more cardio then DC, Cains pace is much more fast paced and aggressively technical, DC just has a heavier hands and his wrestling is better, but Cains BJJ is better. Overall Cain is a little more well rounded then DC plus Cains cardio and size plays a factor.
Jones is a different Animal in his own right, he is a Brilliant Martial Artist, IMO he's more creative and can adapt better to different styles then Cain or DC. Jones fight I.Q is perhaps the best in the UFC, if anybody can beat Cain, Jones has the greatest chance, I see Jones beating DC simply because Jones will dictate the striking and nullify DC wrestling, Jones cardio is also very good, maybe not on cains level but still better then DC. Jones also has looked more Unstoppable in his career then Cain has, Cain has been beaten and has exploited more weaknesses then Jones.
Cains Opponents were all either much slower, lacked technique, were flat footed and one dimensional and didn't possess the speed and cardio to match him.
Jds is a good boxer is heavy hands but his mobility, footwork, head movement and cardio is terrible, Jds is riddled with holes in his game, and Jds has huge problems with Division 1 wrestlers, Cain and Stipe.
Bigfoot is good but he's nothing great, he's also incredibly slow, uncoordinated and tentative.
Lesnar was never the same after his life threatening illness, those surgeries and 12 inches of his Colin removed took a tole on his body, he wasn't the same when he beat carwin, he went into a decline after that.
Jones IMO fought a much better well rounded boxer in Gus. Gus is credentially a far superior boxer to Jds, Gus has far better work ethic, footwork, head movement, cardio, Gus flows with his combinations much better then Jds and Gus has better angles and timing. Overall Gus is simply better then Jds.