... the most interesting American symphonist is the subtle and introspective Roger Sessions.
The New Grove Dictionary of Music and Musicians
Now I know how Schumann must have felt when he first heard the music of Brahms.
Arnold Schoenberg to his pupil Leon Kirchner after listening to a recording of Roger Sessions' Piano Sonata No.2. (Andrea Olmstead, Roger Sessions: A Biography, Routledge, 2008)
The greatest symphonist since Mahler.
Lighton Kerner, The Village Voice
Everybody loves Roger Sessions except the public.
Donal Henahan, New York Times (Roger Sessions' obituary, March 18, 1985)
He always has been an accomplished technician rather than a very original composer.
Harold C. Schonberg, New York Times (March 5, 1976).
[The music] has almost everything but individuality ... and there is little in this score that rises above eclectic academism.
Harold C. Schonberg's 1968 New York Times review of the premiere of Sessions' 8th Symphony (performed by the New York Philharmonic under William Steinberg).
According to some of the above critical opinions, the complete disappearance of Roger Sessions' orchestral music from public performances should be seen as a proof that the music lacks aesthetic merits required for long-term survival even on the fringes of the standard repertoire. According to others, it should be seen as a depressing fate of art music in the age ruled by populist demands for instant intelligibility and gratification.
You can decide for yourself by listening to Sessions' Symphony No.7, recorded live (in stereo) at the October 5, 1967 concert of the Chicago Symphony conducted by Jean Martinon.