FP is certainly the best SF movie ever made, at least until 2001 came along 12 years later, in 1968.
Even after 2001, FP still holds up well. Considering the enormous budget difference in the same movie, and the technology improvements that happened from 1956 to 1968 (actually FP was filmed in 1955, and 2001 started filming in 1964 and finished in 1968). The budget for 2001 was around $11 million, and the budget for FP was around $2 million.
FP was based on Shakespeare's The Tempest, and 2001 was based on The Odyssey, as you probably know. Both derived from great works, with large-scale themes.
On top of that, FP had the 25-year-old Anne Francis, and 2001 had only a two million year old monolith, perfectly flat, with the ratio its sides measuring exactly 1:4:9.
FP is certainly the best SF movie ever made, at least until 2001 came along 12 years later, in 1968.
Sorry, but you can’t leave The Day The Earth Stood Still out of the mix, even if it was a few years earlier (1951).