I voted that my opinion of Keiko was unfavorable before I got married but became favorable after. This is SOMEWHAT accurate, but it is more accurate to say that my opinion of her was simply less before I got married than after, not necessarily bad or unfavorable.
What I mean by that is this: before my marriage, there were times I found her rather shrill and came off as a bit overbearing at times, but not a bad person or character. After marriage, I saw things from the lens of a married man, and suddenly just about everything about her actions or discussions made better sense. Or more precisely, having a wife made me see things more from Keiko's point of view, and beacuse of that, my opinion of Keiko softened and grew much higher.
People tend to talk about the bigger scenes between Keiko and Miles when they talk about her: their arguments about her career being put on hold by going to DS9, how she asks to have him go with her and Molly when the station is in danger instead of staying behind, etc. And I can't really fault her those conversations. They made sense.
But the scenes that really show Keiko as not only a good character but a great wife are the little ones. Like these:
"IN THE HANDS OF THE PROPHETS" - in the beginning, she 'cautions' him about being careful who he shares his jumja with. While this may appear like her being jealous, I look at this as simply a married couple poking fun at each other. I have found that the relationships that last the longest are the ones where some healthy humor is involved... being comfortable with your wife or husband enough to be able to have a sense of humor about things. This scene shows Keiko and Miles ARE comfortable with each other, comfortable enough to have some gentle ribbing now and then.
"ACCESSION" - she sees Miles sad that he is spending less time with his best friend, Bashir. She has good enough instincts to also know Bashir misses hanging out with him, too. Which is precisely why she calls Bashir up and tells him exactly what she told Miles.
"HARD TIME" - throughout the entire episode, she is very patient and supportive of Miles while he is recovering. From her simply leaving him sleep on the floor, undisturbed but just covering him with the covers, to being very soft spoken with him for most of the episode. She even didn't get even angrier at him when he got up and yelled at Molly (which she would have been completely justified to be, given the situation at that moment)... she just put her in her arms and looked at Miles, without saying a word. She knew that was all that was needed... and he left their quarters right then and there. She was fully supportive of him, but had a line that she wouldnt allow to be crossed. And even afterward when she appears at the end, she didn't retain any sort of anger at that incident, just was happy he walked back in their quarters.
While those scenes seem small, they are huge in showing us how great she is. So I'll always be Team Keiko.