This opera is one of my favourite recordings, now even cheaper than when I bought my copy. Pavarotti is heroic and, I feel, preferable to Franco Corelli with Francesco Molinari-Pradelli on EMI. Equally Sutherland is a more 'human' Turandot than Birgit Nilsson. The sound on the DECCA recording is fuller and more vibrant than the EMI.
I have the feeling that the EMI set may be more 'accurate' than the DECCA set, Corelli and Nilsson may be more like the singers Puccini intended to fill the roles, starker, less beautiful, more forceful than Sutherland and Pavarotti. However, because Nilsson's Turandot and Corelli's Calaf are, I feel a little too grand, I prefer the Mehta set overall. Renata Scotto is lovely as Liu, with gorgeous tone, but Caballe has a more radiant voice. The rest of the casting proves stronger on the DECCA set also.
Mehta with the LPO is stronger than Molinari-Pradelli with the Orchestra dell'Opera di Roma, with lots more character and more presence.
The set was already good value but now the Pavarotti/Sutherland Turandot is really excellent value for money, well cast, well recorded and gradually reaching mid-price.