Your choice is among three studio recordings. For me there is too much wrong with the Maazel DG set: Ricciarelli, even at this stage of her career, was already resorting to too many breathy, unsupported pianissimi to cover a lack of top notes, Domingo, as much as I admire him, compared with Bergonzi and Pavarotti seems too beefy in what is often very delicate, plangent music for the tenor and Bruson - is it just my ears? - always has that rather bleaty quality to his tone (though "Gramophone" reviewer Alan Blyth, whose taste I esteem, always raves about his being the best post-war baritone; not for me...) and Maazel's direction is choppy. As for the Federica in the DG, Obratsova (excellent when aptly cast) is a disaster; it sounds as though Amneris has dropped by to chew everyone's ear off. By contrast, Verrett, in this RCA recording, tames her opulent sound to be both more vulnerable and incisive, inflecting the words sensitively. Cornell MacNeil uses his lovely, pharyngeally resonant, true Verdian baritone tastefully, Moffo sounds pure and innocent while despatching the coloratura easily and and Bergonzi is his usual model of style and restraint, but still rises to the passion of "Quando le sere al placido". Cleva conducts unobtrusively and really supports his singers. In the Decca, Caballe sounds too matronly and Milnes a bit too woolly compared with MacNeil - but Pavarotti is great and the conducting more exciting. So, my choice for this RCA is set is clear but I can understand anyone going for the Decca - however, I would avoid the DG.
This 1964 recording of this somewhat neglected Verdi masterpiece offers splendid performances from all soloists. Anna Moffo is peerless in these romantic/tragic heroines (Lucia and Gilda were two other great roles) she sings superbly throughout and captures the youthfulness and vulnerability of the character like no others. Carlo Bergonzi is as usual all elegance and intelligence and he too sings superbly. The rest of the cast is also unusually strong with such singers as Cornell MacNeil, Shirley Verrett, Giorgio Tozzi and Ezio Flagello all at their finest. Fausta Cleva conducts masterly. Chorus and orchestra are excellent and so is the sound. A must for lover of great singing and great music.