Harnoncourt is a strongly individualist conductor, and his individualism is much more strongly pronounced in the 1986 B minor Mass than in the 1968 version. That's why quite a few reviewers prefer the earlier version - finding the later one mannered, even eccentric. I understand their views, though I don't share them.
Like many renditions of Bach's monumental B Minor Mass, this one puts forward a musical argument: in this case, for the use of a vocal ensemble made up of ten soloists rather than a choir. Minkowski's approach may be historically aggressive, but the sound is unstintingly lovely and the pared-down arrangements shed an interesting and unusual light on this most familiar of the baroque masterworks. Highly recommended to most classical collections and all period-instrument collections.
From the notes: "The Story of This Recording: Jenny Lind's contribution to the first performances of the B minor Mass has a parallel in this recording where another opera singer, Elizabeth Schumann, is the soprano soloist in the first complete B minor Mass to be committed to disc. While the Philharmonic Choir and London Symphony Orchestra needed much of the rehearsal time, sessions were so arranged as to take advantage of the presence in London of Elisabeth Schumann and the celebrated baritone, Friedrich Schorr, both under contract for the summer Season of opera at Covent Garden. Walter Widdop, the tenor, was also singing there, but he and Margaret Balfour, a mezzo soprano who was greatly esteemed for her work in oratorio, both lived in London. The conductor Albert Coates, normally associated with Russian music rather than with Bach's also had a comittment at Covent Garden, but was able to devote his complete concentration to the recording because his operatic performances were not scheduled until June. The recording was issued promptly in November 1929 on seventeen plum label 78s."
A visionary synthesis of the art of a composer who, here more than anywhere else, gives meaning to the world in which he lives, and reveals to us something of what lies beyond, the Mass in B minor is one of the supreme peaks of Bach’s music. Raphaël Pichon and his ensemble Pygmalion explore this universe which gives utterance to the mysteries of incarnation and death.