Does it have other qualities that make it worth reading despite the off the charts levels of Oedipus complex?

Oh, yeah: I actually like it as a novel and have a much better opinion of the central couple's long-term chances than Renault does; I consider it her one real successful instance of contemporary m/f. But the male lead's relationship with his mother fits right into the Renault Oedipal matrix. I don't think she was incapable of writing other kinds of maternal relationship, but she definitely had a default.