I get the idea that Simon was a level above Williams, as the statistics will tell you. Having said that, Williams seems to have been better than his record suggests. Ali made Shavers fight him, in order to get a shot at the title. He obviously thought that he would sort the men from the boys!
What a menacing sight Abe is, a kind gentle one tho at heart but his appearance is as far as it goes his ability was very limited.
I’d have to go with Simon by knockout in the later rounds. Roy Williams was a tough customer and wasn’t lacking in ability, but he invested too much of his career as a sparring partner for top fighters, which is why he often choked when he fought top competition. Williams choked badly against both Holmes and Shavers. The worst thing an ambitious young fighter can do is become a mainstay sparring partner for other top fighters. It’s okay to get experience, but once it becomes a regular form of income it’s rare not to develop sparring partner syndrome.