They hype around "Business Proposal" was a bit overblown, in my opinion. It's certainly a fun show to watch, and it has a lot of very well-constructed moments. But ultimately I liked those moments instead of how the story came together as a whole.
A lot of the hype was around Kim Se-jeong and it's well-deserved. Her acting is effortless, completely natural, and genuine. The small group of actors who make up her work team are all a bit over-the-top, but it plays well off her more subtle performance. Those scenes with her co-workers were the ones I enjoyed the most throughout the series.
So many of the over-arching story threads felt like they were abandoned or wrapped up too neatly, though. The one that felt most neglected was the resolution with Tae-moo's grandfather. In the end we don't get any resolution between him and Shin Ha-ri - just a brief comment about how he's still in America. It's like they ran out of episodes to fully close his part of the story.
I still recommend watching "Business Proposal", but don't expect too much from it plot-wise. Watch it for the well-developed characters and the brilliant performance by Kim Se-jeong.