Pretty good?
The teams he had in the early 70s were great and they were always in contention throughout his first term as their manager.
During his first tenure with the Orioles, he managed 14 full seasons. They won 100 games 5 times (3 of those on a row) and he had only 3 years where the team failed to win 90 games (2 of those were strike shortened). He had a partial year in 1968 when he took over the club at midseason and he had them on a pace to win 96 games. He retired the first time after the 1982 season, and the O’s won the World Series in 2983 with a team Weaver built.
Camden Yards didn’t open until 1992, 6 years after his second tenure in Baltimore.