The 2-star rating given by the reviewer below is typical of listeners who can hear only the surface of a performance. Giulini made a studio Verdi Requiem in 1963 that by common agreement is a classic of the gramophone, and around that time he took the same Philharmonia Orch. and chorus into Albert Hall for a Proms Concert version (there's yet a third reading, live from Royal Festival Hall, also on BBC Legends but in mono). When choosing which Giulini to buy, bear in mind that the EMI is nearly a perfect match of great singers, musicians, and conductor--the Philharmonia Chorus was arguably the best in the world at the time, due to chorus master Wilhelm Pitz. This live reading comes close to that ideal, except in the solo singing.
It goes without saying that this is a special performance--tender, humane, reverent--but it's also true that the sound is fairly basic FM-radio stereo. It sounds best in soft passages or when the soloists are singing and gets congested in volcanic eruptions like the Dies Irae (not to the point of being unlistenable, however). The quartet of English soloists do well, even though they aren't as authoritative as their studio counterparts. The only serious lapse is the Libera me, when the soprano, Amy Shuard, can't manage enough fervency or vocal weight.
What this CD comes down to is Giulini, and he is at his finest. This isn't a carbon copy of the EMI recording; he's freer, more flexible, less studio-bound. In addition, there are two very attractive fillers: a Vespri Siciliana Over. from 1963 and Schubert's late E-flat Mass, D. 950 from 1968. The 55-minute Scubert work, almost totally for chorus and orchestra, is a masterpiece that Giulini loved, and his reading is among the most inspiring I've ever heard.
In sum, a five-star set if one ever existed, but be aware of the limitations in the sonics and the solo quartet.