An interesting one as Morrissey was very open about how challenging the vocal was for him. I think he did a great job elevating what's essentially a good song. As @Gregor Samsa said, it's a style that I wouldn't mind him exploring more.
Probably the weakest version on 'California Sun'. It's pleasant enough, and Morrissey does a decent vocal - but unfortunately he doesn't get anywhere close to the swooning brilliance of Orbison's original vocal, and the music arrangement isn't different enough to give this a unique selling point. The worst aspect is that in the original song, it builds and builds to that big final note - which Morrissey clearly can't do as he doesn't even attempt it, so it ends in a very underwhelming fashion. (5 out of 10.)