To be fair, I can totally see it being the case that when Miles raised the issue of transferring to DS9 he put a rather rosy spin on the situation (heck, perhaps he wasn't given an honest depiction of the situation himself, or just didn't believe it would be as bad as it was). And let's not pretend he isn't the type who'd love the idea of the challenge of putting the station back together. As he says in "Emissary", when Keiko first saw their quarters she talked about moving back to Earth. It's not as though she ever claimed to be happy about moving to the station.
If you want to look at it as who sacrificed more, I think Keiko wins.
I also think that if she had been happy all the time and there hadn't been any tension in their relationship then we'd see exactly the same sort of thread we have right here, except the complaints would be more along the lines of, "That was so unrealistic! Keiko threw away everything when she moved to DS9 but then was the perfect submissive little wife when she got there! How stereotypical!"