I have not watched the orginal Japanese parent story and cannot offer comparisons.
However, I must say that this version is a masterpiece and an emotional rollercoaster. I was tearfull when I had watched the first episode but the drama had pulled me (which does not easily happen). The story offers different versions of motherhood in different context, which is what I mainly liked about it.

The acting was wonderfull on all parts. Many love Lee Bo Young and I can see why.
The OST where not that memorable but amplified the overall feeling of teh drama.
I have rewatched the drama and it still remains an amazing drama.