[I have little to add to Terry Serres' really quite beautifully written and considered review. Indeed, I suggest you read it first, before reading my comments.]
The main thing I want to add, aside from endorsing everything Serres has said, is to point out that TV director Katie Mitchell and her co-workers have made a rarely-used form of television opera production in that the opera is opened out as a movie would be -- that is, it is not confined to an opera stage, but rather is filmed in beautiful British surroundings using the actual singers who recorded the music. What is striking is that at times the singers are seen actually singing their parts but at other times they are filmed as actors with, often, interior monologs being sung by them on the accompanying soundtrack. This is done so seamlessly that it took me a while to realize what the director had done.
Further, the singers are particularly visually apt for their parts. Mark Padmore, aside from being a marvelous singer, becomes the embodiment of the eerie Quint. Lisa Milne looks and acts the part of the innocent but plucky young governess, and she sings beautifully. Diana Montague, in a former time a leading lady of opera -- I still remember her stunning Iphigenia in Gluck's 'Iphigénie in Tauride' -- is simply unbeatable as Mrs. Grose. The two children, Miles and Flora, are convincingly played and sung by Nicholas Kirby Johnson and Keturah Day. Catrin Wyn Davies makes an effective Miss Jessel.
Musically the direction of Richard Hickox, leading the City of London Sinfonia, cannot be bettered. This is a psychologically deft performance.
This is easily one of the best opera DVDs ever made. I had earlier praised (and still like) the staged version from the Schwetzingen Festival, but this one is dramatically much more effective.