Hwarang: this was the first k-drama I watched and that's the reason for my high rating. I believe though, that if I watched it now I wouldn't enjoy it as much. The story is nothing unique, the fl is annoying and Go Ah Ra's acting in this unfortunately doesn't help. It is mostly romance based and doesn't give space for historical events. In general watch it if you have nothing else to watch.
Bloody romance: (I've dropped this myself). It is visually pleasing, the ost is nice and I was quite impressed from the cinematography. But I was also waiting for a strong FL based on the plot, and not only it wasn't that (until episode 17 at least), but she was annoying and even though she was supposed to be an assassin to survive, she couldn't even kill a fly and she put everyone around her in danger. So again it depends on what you are expecting to watch.