This is a great and rare performance. The sound is excellent. I have posted a transfer of the BSO - Charles Munch recording. Unfortunately the dynamics of the record are not as good a this version. This version is more energetic and tighter than the BSO recording. Maybe Mitchell was more comfortable with new music than Munch? Bolet's playing in the Elegy:Adagio with BSO seems a little more fluid than with the NSO. Otherwise, I think I prefer the NSO version. Great to hear the differences in the two performances which I gather were within a few months of each other. Thanks for posting.