I've always thought Jones would win this fight and maybe even finish Cain, though back in the day if you said this the entire forum would flame you into the living death.
I think Jones' long range kick strategy would be fairly effective against Cain, and Cain, would try to use his double leg take downs and leg kicks. Those leg kicks interest me, they'd be huge factor imo because more fighters who have been adept at leg kicking have also had a weakness to TD's, thus throwing those kicks is like asking to get taken down and elbowed into oblivion.
After seeing Jones vs. DC I think most people including Cain himself changed their opinion on the matter of Jones vs Cain to Jones can definitely beat Cain, because Jones began to dominate DC at the latter end of the fight.
There was a gif of Cain's reaction to Jones beating up on DC throughout the fight that really says it all. I think Jones is a better fighter then Cain himself thought thus the surprised reaction.
That being said, this is no EASY fight for Jones, but I think we should note DC has an iron chin whereas Cain's has been suspect, and if he gets hit with something like a spinning back elbow I think he doesn't take it as well as DC would have. If Cain fails to take Jones down and has to fight standing I think the long range fighting of Jones would eventually win out. Cain has to also be wary of those sneaky chokes by Jones because his neck will be open if he's shooting in for a power double.
I favor Jones here but of course it's Cain so not by a lot.