James Gunn’s 'SUPERMAN' currently has a higher Rotten Tomatoes score than: • All 4 Christopher Reeve Superman movies • Bryan Singer’s 'SUPERMAN RETURNS' • Zack Snyder’s 'MAN OF STEEL'

The claim states that James Gunn’s 'Superman' has a higher Rotten Tomatoes score than all four Christopher Reeve Superman movies, Bryan Singer’s 'Superman Returns', and Zack Snyder’s 'Man of Steel'. According to the sources, James Gunn's 'Superman' has received critical praise and holds the best Rotten Tomatoes score since the Christopher Reeve era, which suggests it surpasses all four Reeve films.

Additionally, multiple sources confirm that it has already surpassed Zack Snyder’s 'Man of Steel' and Bryan Singer’s 'Superman Returns' in terms of Rotten Tomatoes scores. While exact numerical scores are not provided in the search results, the consensus across these reputable entertainment news outlets supports the claim. The only nuance is that while it is stated to be better than all four Reeve movies collectively, individual scores for each Reeve film are not explicitly listed; however, the phrase 'best Rotten Tomatoes score since Christopher Reeve movies' strongly implies it is higher than each of them.

Therefore, the claim is mostly true based on available information.