Out of all the "fake relationship" dramas out there (granted, I have only seen a few), this one had the most justifiable premise -- which still does not mean that it was entirely believable :) All the same, it was interesting to see how the show tried to balance the comedic and the truly dramatic components.
On the positive side:
* The leads, for once, are more fleshed out and interesting than the supporting characters! Maybe it's because they are not cast to be "the most beautiful" or "the most interesting" (both lead actors are very attractive, obviously, but they play the parts of ordinary people). The supporting characters have their own story arcs, but are definitely much more one-dimensional and somewhat caricaturish.
* The story flows relatively well and the events make sense (until the last episode or two, at least).
The negatives:
* That last, artificial, incomprehensible dramatic turn -- why? what for? (I refer to the "Mongolia trip" for those initiated to the series.) It made no sense. I wondered if it was a translation issue, and that maybe I missed something, but I watched those episodes with two different sets of translations, and it still made no sense...
* The show kept coming up with, and changing, the "leading theme" (or, to put it differently, the aphorism it was trying to explore; the zeitgeist it was trying to tap into; etc.): First it was the patriarchy; at some point it was finding the special small moments to be happy with things; then it was something weird about being unconventional... I think the overall trajectory of the show would have been more enjoyable and less jarring if the writers had picked one leading thought and stuck with it.