If we are talking in depth about the relationships in the end I feel that Ron and Hermonies relationship was the better one as the trust was immensley better than what Harry would confide in Ginny. Ron and Hermoine both go on the horcrux hunt with Harry, whereas Harry does not even confide in Ginny about what they are setting out to do.
Even though in the book J.K Rowling speaks of Harry's longing for Ginny he is still able to leave her without saying goodbye when thinks he is off to meet his death at the end of the last book. It does say that if he talked to her he thinks he couldn't go but isn't this more selfish love instead of giving her the chance to say goodbye and telling her why he must die while he has the chance instead of leaving her pondering for the rest of her life why he left without saying goodbye? I think if it was Ron in this situation no matter what he would definetly say goodbye to Hermoine. Yet Harry and Ginny have taken their relationship to another extent which neither Ron nor Hermione dared to take. Ron and hermione are confused of their feelings for one another. therefore I conclude that Harry and Ginnys relation was better as theirs was truest love