Tippett's first symphony is best described as an explosion of counterpoint. It is an intensely active work, difficult for conductors and orchestras to realize convincingly and also relatively difficult to the listener - even the slow movement features a rotating ground bass set to a formally very complex structure. It is, however, the most immediately convincing movement - rather remarkable, in fact. The problem with the work is that as it moves towards its final harmonic resolution in the final movement, you get a strong sense that the whole thing is more gimmicky bluffing than anything of real substance (for instance the petering out of the music to the gradually louder final cords). It is worth hearing, definitely, but I harbor strong doubts as to whether it is the masterpiece some commenters have claimed it to be.
The performances cannot avoid struggling, and while Hickox does have an admirably clear vision of the work, the music falls a little flat in certain parts where one suspects the composer envisaged more ethereal, airier textures. The music also sounds a little monochromic; still, I doubt there are many better performances out there. The performance of the piano concerto is overall more impressive; Shelley is a remarkable soloist who shapes the melodic lines very convincingly and the imaginative textures come across impressively. But whether there is more to this work than the textures and certain inventive but short-breathed isolated passages, I don't quite hear it. So to sum up, while this is a fine release, I am very uncertain that the music really has many lasting qualities - I am open to the possibility that it is simply this listener who fails to see them, however. The sound quality is at least excellent.