I'll admit that I watched it recently, 5 years after it aired and I may have enjoyed it more had I watched it then, the beautiful scenery and production would've blinded me. But since it's not the case and kdrama since then have a better production so it's not the only high budget drama anymore, I'll say it really wasn't worth watching.

The story didn't move at all, they spent so many episodes going back and forth, and they would go as much as 5 episodes without nothing substantial happening. The story could be condensed in a 1h30 movie, I'm not sure there was even a story worth telling to begin with.
The second leads helped me get through the show, their storyline was a little more interesting, but the second part of their story was a little boring to.
The bromance was on point though.