Burt who saw Ike fight in his prime considered him the best lightweight he ever say, something I give credence too though head to head with Duran I'd have to take Roberto.
I think that fight is a toss up. Considering what he had to contend with outside the ring he achieved a great deal becoming one of the better Lightweight Champions. The 1940s was no joke when it came to tough contenders. Williams stood out.