Here is Goran Forsling's fine review of the latest incarnation of the Met's 1940 broadcast of Un ballo in maschera. His judgment: this version is sufficiently improved over previous transcriptions, to be considered a MusicWeb International RECORDING OF THE MONTH for December 2013.
"A Recommended Version of Jussi's 1940 Ballo,"
Journal of the Jussi Björling Societies of the USA & UK: Vol. 22
, Article 8.
Available at: https://scholarsarchive.byu.edu/jussibjorlingsociety/vol22/iss1/8