STORY : all the love stories felt disconnected and suffocating. ppl "fell in love" with each other just to carry the plot along, not b/c it made sense. the first 1/3 of the drama was definitely the best part, but after that, let me tell you IT DRAGGED.
also ppl switched their affections like every other episode.
one thing I DID LOVE was the fact that it was a drama set in Goryeo period. Korean dramas are always set in Joseon period (which is fine and all) but I loved seeing a drama who's style was more that of Chinese since the Goryeo period was more heavily influenced from China.

ACTING : some actors (basically the princes {sans baekyun sorry}) did either a good acting job or a really good one, but none were amazing.
and no matter how much I love IU's voice, so did NOT deliver in this drama.

MUSIC : a 50/50 for me. there were some tracks that were perfect and others that were really bizarrely peppy and upbeat during sad moments that really threw you off and didn't fit the overall drama.

REWATCH VALUE : heck no.
it dragged and I couldn't wait for it to be over, but I'm a completionist so I had to finish even tho I almost died of boredom many times

OVERALL : 4.5/10 for me plot is the most important part of a story and that was the biggest flaw with this drama.
but I have to say that the costume designs and sets were all immaculate.