I think I'm kind of an idiot about classical music, so I can only make basic comments here. Music for Percussion, Strings, and Celesta is one of Bartok's greatest works, and as such is one of the greatest works in all of Western music. Despite the ostensible eminence the celesta is given in the title of the piece, the dominant keyboard instrument is piano, which is part of the percussion ensemble that serves as the anchor for two string sections. The piece is an amazing exploration of opposites, especially its use of chromatic and diatonic elements. The first movement is a chromatic fugue for strings, and Bartok's use of changing meters gives it a watery effect. From the first movement you can already tell it is one of Bartok's best compositions, simply because every note is so exceptionally placed and the flow is so natural. The second movement is an exhilarating allegro, a tight mesh of melodic themes manipulated with rhythmic and metric variation. The third movement is intensely chromatic "night music" with obscure tonality and fragmentary melodies. Best of all, the fourth movement, where diatonic considerations come to the fore and it is the most varied in rhythm, melody, and pitch, but still structurally sublime. Throughout the piece, the key subjects are changed into new subjects, which undergo their own changes, and eventually morphing back into previous themes. This is done with such uncanny perfection that the music really feels like it takes you places. I know that sounds cheesy. I won't discuss _The Miraculous Mandarin_, though it is very good as well.
Get this if you want to hear a divine performance of one of the musical universe's greatest treasures. (Sorry for the CAPS above, I know it's annoying.)