All of the "regulars" in the "Vintage" Forum would enjoy having a copy of Fred DeLong's "DeLong's Guide to Bicycles and Bicycling" from 1978. It can be found at Half Price Books and on E- Bay. It is the best overview of bike technology circa 1978.
Fred DeLong put together a chart of the tubing being used in 1977. It showed that Reynolds 531 was available in 11 different gauges, from silly thin to beefy tandem gauges. And, Columbus, Tange, Vitus, and Isawata all did what Reynolds did: they made ultra-thin, ultra-light gauges for special racing bikes, and beefier gauges for touring bikes and tandem bikes.
The concept of "best" in tubing is often muddied...some folks assume thinner and lighter is "better". However, the "best" tube for a given bike depends on the purpose of that bike, the size of the bike, and the size and weight of the rider. Isawata Extralight 015 Alpha tubing would be SCARY on a touring bike designed for a 200 pound rider and 100 pounds of gear and cargo.