I just looked up Clive Barnes's review in The New York Times: "He probably has the most purely beautiful voice in the English‐speaking theater, but it is a voice not just of empty beauty, but a voice that has an almost moral tone to it. It is a voice to stir rather than lull, a voice where you remember the poetry it caresses rather than its own special, vocal glories. For the fact is that Mr. Scofield is fundamentally a plain, unvarnished actor, completely at the service of his art. Nothing is wasted on false effect—from his craggy, troubled face, his noble manner and compassionate eyes, nothing is permitted that might strike a false note in this Prospero of renunciation and grandeur. It is all so beguilingly direct—a most beautiful and memorable portrayal."
I also had the good fortune to catch him in Uncle Vanya at the Royal Court and it's a matter of lasting regret that I didn't get to see him as Salieri in Amadeus.