Loved it! It was better than the Chinese version in many ways, but I think I enjoyed them just about equally. Equal enjoyment doesn't equate equal quality. I think the overall story was better here. The found family was the best I've seen in a drama (besides Love is Science? but that is a different type of found family). In this version THERE WAS NO LOVE TRIANGLE. God that was so much of a blerg in the Chinese version especially when you compare it to the lack of one in the Korean version. The lack of the love triangle meant that they could do Hae Jun's character SO MUCH JUSTICE. I loved his character. I loved his acting. I never felt bad because he didn't get the girl and you could tell that he played an equally important role in the sister's and the family's life.
(We of course felt bad for him because of his "family situation" but not because he earned second place in his sister's affections - which became the case in the Chinese one. Then that made the relationship between San Ha's equivalent and the sister more central, overshadowing parts of the story that were better fleshed out in the Korean version.
Also, Hwang In Youp's acting was FAR superior to his counterpart. That, of course, is no surprise, because Hwang In Youp is a genius and we're all so so so so so so happy that he finally has his lead role that he deserves.
On the other hand. I will say that I didn't feel the chemistry as much. I felt his longing and love for Ju Won, but I never felt here's for him. It was almost like *snap* she's in love with him and it happened so fast and with nothing to support it and her character kind of felt flaky ever after. NOTE, I saw someone say they didn't like her character/the actress didn't do a great job. (This was before I watched it and why I held back from watching it for so long). I 100% disagree. I thought she did an excellent job. She was the glue that held the family together and she did a perfect job at it. It isn't her fault that they didn't do her justice in giving her the opportunity/reasons to fall in love with San Ha (besides the fact that his love is so apparent and genuine and all-encompassing, but having someone love you that much doesn't equate you loving them, and I just was never convinced. They fit together well and were a cute couple, there was just never the spark that got Ju Won there.)
On that note, while San Ha's counterpart's acting wasn't that good, I did think the couple from the original Chinese version had chemistry that their Korean counterpart lacked. Which is confusing. How can a poorer actor be in a couple that has better chemistry? I think it was directing/how the story played out. I still remember the scene where San Ha's counterpart says he's going to marry her early on... you just have to watch the whole thing.