Just finished this last night. Great drama, one of my favorites.
As for the ending... (SPOILERS)
It seems some people think that the two of them both died. People who think this, don't pay enough attention. While there is one or two things that can get you to think this way. They are just tricks to make you anticipate what the ending will be.
They are clearly both alive at the end. If she were dead, why would her vision still be impaired? If they both died, why would Jin Sung and Hee Sun only visit Oh Soo and not Young? The events in the drama end about a year before the ending I think, and shes says something that he had been there for 6 months and that he told Secretary Wang not to tell her or something. People make trips once a year to visit a grave, and Jin Sung and Hee Sun talk about giving him a certain flower last time. At where? the funeral? That makes no sense. They either are talking about visiting the cafe or the other Oh Soo. I can go on and on with examples, but all you have to do is rewatch the final 15 minutes or so, and it becomes pretty obvious.
Overall, a great drama. The only think I probably didn't like was that Jin Sung stabbed him in the end. Given his loyalty, even with his family in danger, I don't think he would have done that so easily. He had no visual representation either of how much in danger his family really was. There could have been other ways to avoid the situation anyways.
