This was done at the Met, and broadcast on PBS, and the cast included the most distinguished singers of the time so it should have been top-notch. Unfortunately many of the singers had off-nights or just weren't as great as cracked up to be.
The three largest roles are Alberich, Wotan, and Loge, and all three performances are flawed in one way or another. Alberich is played by the great Ekkehard Wlaschiha, but there's something very wrong with his acting here: I think he was trying to be funny, and his clownish delivery distracts from, and almost neutralizes, the menace which his character is supposed to have. James Morris is a fantastic vocalist but his acting is both wooden and exaggerated at the same time. And Siegfried Jerusalem as Loge is a mess.
The larger of the two giants ("larger" meaning having more lines) is Fasolt, and the singer, Jan-Hendrik Rootering, sounds old and woolly, and acts poorly. The only really solid performances are in smaller roles: Matti Salminen is powerful and menacing as Fafner; Christa Ludwig is very smart and sweet-sounding as Fricka and her formidable celebrity-value--she's a superstar-veteran from the old days--makes up for her small vocal size. Super-genius Heinz Zednik as Mime anticipates his spectacular delivery in the later chapter of the Ring (Siegfried), and the Rheinmaidens are wonderful.
So this is definitely the worst of the four Ring operas in this particular production.