Thanks to baverty (and sandy beech) for alerting me to this version. I am very fond of The Walker Brothers cut, believing it to be their finest, in advance of other more commonly-played tracks that were big hits for the guys.
Much as I love the Everlys' close harmony, on this occasion I would go for The Walkers' cut. Something about the whole presence on their recording: Scott in superb voice and that Spector-like magic. The normally appealing tremor in Don and Phil's voices seems to detract a little from the song's impact on this occasion.