The four albums on this set date from between 1957 and 1960, the earliest being "Miles Ahead". That's notable for being Miles' first collaboration with Gil Evans, which partnership progressed to "Porgy & Bess" and "Sketches of Spain", all three of which featured Miles playing against a large ensemble. In contrast, "L'Ascenseur pour l'Echafaud" was recorded during Miles' late 1957 tour of France, when he was invited to provide the score for Louis Malle's film noire, for which a quintet was used.
In order of preference I'd start with "Porgy and Bess", where Evans' arrangement provided a shimmering background for Miles' lyrical playing of Gershwin's masterpiece, producing a stunning version of that folk opera. "Sketches of Spain" was inspired by Rodrigo's Concerto, and begins with the transformation of that classical composition, followed by de Falla's "Will o' the Wisp" from his ballet "El Amor Brujo", the three remaining tunes having been contributed by Evans. I don't think "Miles Ahead" quite reaches the same heights, maybe because it was the first such collaboration. Just as an aside, the late Philip Larkin praised the surface texture produced by the shifting background of brass, French horns and woodwinds; the only problem from his point of view was that, as jazz, it was practically non-alcoholic! Finally, "L'Ascenseur pour l'Echafaud" is a film soundtrack that was integrated with the screen action, but is less effective when heard in isolation.
Judged on its own terms, this is three classic albums plus an odd one out, but sound quality is excellent, and anyone needing to replace their worn vinyl should jump at the prospect.
I bought this set recently as a gift for a friend as I had known (and at various times owned the vinyl originals) and loved them over a period of fifty years. Looking back across that time these albums (especially the collaborations with Gil Evans) are as 'fresh' today as they were when first recorded and still considered by many to represent, not only some of the finest music (I hesitate to call it 'jazz') Davis ever recorded, but some of the finest music recorded...period. They stand testament to a wonderful and unique musical partnership.
The plus with all these Avid releases is that you get much for your money. I know that much of this can be found elsewhere and it is now a case of the buyer doing a little research and deciding for themselves if what is on he fits their requirements. Those who have the originals can quite cheaply replace their old LPs and play the CDs in the knowledge that sound is top notch.