Both players were known as power hitters with Howard becoming a force for the Washington Senators towards the end of his career. Howard came up as the cleanup batter for the LA Dodgers of the late 1950s and 1960s. He was on the 1959 and 1963 World Series Championship teams. However, it was his time in Washington that stood out. He hit 40+ homeruns from 1968-1970, calumniating with his 1970 season where he hit .283, 44, 126. Thomas never matched those numbers but had good seasons of his own. The Mets will always remember his 34 HRs he hit in their inaugural season of 1962.
Howard had 5 30+ HR seasons (3 40+ HR seasons). Thomas had 3, two with the Pirates and 1 with the Mets. Howard had the more dominating career but also benefitted from playing for only two organizations for the majority of his career. (Dodgers and Senators) Howard hit .273,382, 1119 with 1774 hits, 172 BB and 1460 Ks. His career OPS was .851. Thomas, who played 3B as well as the OF, hit .266, 286, 952 with 1671 hits, 484 BBs, 894 K and a .774 OPS. Howard was more of the core type player, as Thomas was asked to be a piece. Thomas finished his career playing for Pittsburgh (1951-1958), Cincinnati (1959), Chicago Cubs (1960-1961), Milwaukee Braves (1961), New York Mets (1962-1964), Philadelphia (1964-1965), Houston (1965). back to the Braves (1965) and back to the Cubs (1966).
It is obvious to tell who was the better overall player, however, Thomas could have been a great fit for the right team at the right time. But it seemed the opposite happened. Thomas was traded by Pittsburgh to Cincinnati for Don Hoak and others and the Pirates won the World Series in 1960. Thomas was out of Cincinnati after 1 season and the Reds won the NL Pennant in 1961. He was on the Phillies in 1964 when they had their historic September collapse.