This drama is really good. While sometimes it is over the top (but honestly, which k-drama isn't?), it doesn't have any unnecessary plot twists. Instead it has good, consistent writing and character development with a satisfying end.
All the characters, not just the main ones, have a well developed personality and sometimes you like one of them even more than the mains (president Park was just doo adorable).
All in all, I would always recommend to watch and have watched it twice at this point. It got my best friend into K-drama as well.