Well I know that rating many aspects of this that way would give it higher rating but I just could not, eventhough I considered 6/10, I believe that 5/10 is fair rate - but it is not bad!!
What is important - Seo In Guk is one of my favourite actors so I had to watch it - and his acting here is 10/10, but I could not rank whole drama higher only because of it. Music was great. Plot - I wished it was full length drama with at least 10 episodes - then it would work perfectly or even full length movie, cause plot was fun and perfect for fantasy romance.
It was more like a few mv's with some plot . Also there was no crazy budget - but it is clear that there were not supposed to be.
Big advantage - you can watch it on youtube - and for people who like short episodes it will be perfect. If you need something short between other drama releases.
To sum up - not bad, but not good.