In the modern era (new cloth) he is in the top five, along with Earl, Sigel, Buddy and Varner (Mizerak's best years were pre new cloth). It's impossible to rate these guys against players like Greenleaf, Mosconi, Lassiter and Worst. They were the greatest of their respective eras.
To go one more cut deeper - Earl may have been the greatest tournament 9-Ball player of all time. He made the 9' table look like a bar box. Like Shane he had the break down pat. He was the best of the best in his era. Buddy probably won more tournaments than anyone ever. He crisscrossed the Eastern U.S. playing nearly every week for over twenty years. He played in any tournament he could find with a $1,000 first prize or more, many of them on bar tables. These were not easy tourneys to win, with many very strong players in the field each week and Buddy won consistently. So much so that to see him finish second was a surprise. I once asked Buddy if he thinks he won 200 tournaments in his life and he responded, "Way more than that!" Sigel was virtually unbeatable if he got to the finals, at one time winning eleven final matches in a row (against guys like Earl, Buddy, Nick and Efren). All on big tables! No one will ever do that again. Sigel had far and away the best TPA (Accu-Stats rating) in every tournament he played in. He would make four to five errors per hundred shots and the next best were in the seven to eight range. Pat Fleming still has all these stats. Nick was player of the year in 1987 I believe, the year he won eleven major tournaments! He was the best player pound for pound that ever lived. Nick was fearless and not intimidated by anyone. He was quiet and not one to boast. When asked how he played against some great player Nick might say, "Go get him and we can play right now!" He beat Efren in a challenge match in the Philippines years before Earl's big match. Not many people talk about that match.