Tommy is by far my favourite fighter, but he just doesn't have the legs to keep Benn off him at 168, he was too far past his best. A prime Thomas Hearns at 160 though would likely catch Benn before Benn catches him though and stop him
I've voted Benn KO but only because Benn has the footwork to get inside and land and I think that's what he would have done. Tommy also had the power to KO Benn no doubt, its a 40/60 in Benn's favour I think.