Be prepared to hold onto your horses and definitely don't close your eyes! Though this is a short Sageuk coming in at a measly 24 episodes (IKR!), it certainly has all the feels and annoyances and amazingness that makes up a typical Sageuk.

Story (9.0):
I'm literally writing this as the last episode is finishing and I'm watching this last scene and getting goosebumps and shivers; what an amazing way to close the drama! I've heard some negative comments about this ending, but honestly it was the best way it could have ended in my opinion. And it's not even your typical Sageuk ending where everyone both good and bad beside the main character seems to die (only kind of joking); instead we see a beautiful finale that ties in with the first antics of our main couple and leaves you to wonder why all those other dramas focus on closure by successful revenge and conquering.
But don't get me wrong: the whole last half of this drama is mostly about trying to get revenge, and there are PLENTY of sorrowful and tearjerking scenes especially leading on from the 1/4 mark. If the beginning of the drama didn't clue you in, I don't know what would. This is a Romeo and Juliet style story (don't worry, it doesn't end quite the same).
There were a number of romantic couples in this drama, and while Se Ryeong and Seung Yu's was very fun to watch, especially in the very beginning and as the story came to a close, I found the love story between the Princess Kyung Hye and Jung Jong to be just as enticing and especially around the half way mark, even more fun to watch. Honestly, the Princess Kyung Hye was more interesting at times than our main character Se Ryeung (I guess I could call her Princess as well), and I loved seeing Kyung Hye's relationship both with her cousin Se Ryeung and her husband Jong morph and change over the course of the story.
I've painted this story in a highly positive light so far, but there were some parts I found excruciatingly aggravating. However, as I go through and enumerate, you'll probably see that it isn't isolated to only this Sageuk.
First off, most of my frustration from this story happened from the 1/4 mark the 1/2 way mark. Seriously, I watched the first 6-7 episodes in great joy, then draaaggged through those next 6-7 and then flew through to the end.
BEGIN RANT:
My problem with these episodes were these stupid choices and mistakes and misunderstandings and mishaps and all this gooblety gook drama that I really didn't want to see that I realize needed to happen for the rest of the drama and I'll admit made Se Ryeung's later actions so cheerworthy but in reality made me really want to skip scenes and indeed I found myself reading recaps to find the scenes I wanted to watch so I could get to a place I really wanted to see and I've lost sight of where I was going with this rant, but seriously, WHY! AGH!
END RANT.
Heh, the last half was worth all the drama though, and yes the drama was the basis of the whole story, but still, meh, Se Ryung was a bit annoying in these portions.

Acting/Cast (9.5):
Ahhh! So many crying scenes! I think most of the time Princess Kyung Hye was on the screen, she was crying!
But wow, Princess Kyung Hye blew me away, especially in the scene where she and Jong are tearfully looking at each-other... Actually, that whole episode was amazing on her part. Whenever her chin wobbles came into play... Dagger to the heart! ;(
The rest of the cast was mostly very good, though I found Song Jong Ho's (Myeon's) acting to be a bit over the top at times. Especially... nvm that's a spoiler.
There was also one scene that stuck in my head where there was an army of soldiers cheering that was sooo fake.
Beyond that, our main characters definitely didn't disappoint, and all the conniving and scheming and backstabbing politicians and their incompetent rivals were pretty well cast; I thought Se Ryung's father was very well cast especially whenever his character had semi-redeeming (who are you kidding, he can't be completely redeemed) moments like the last part of the finale.
The main couple was well cast and were very good together, but they definitely don't top my favorite couples list. Maybe 5th place. It's not totally their fault though because I've got some really strong couples on my list. Props to Woon and his Orabeoni girl love...
Final person I really need to commend would be the young King Dan-jong played by Noh Tae Yeob. Those sorrowful eyes of his can really strike the heart and helps his excellent portrayal of a young desperate king who feels trapped and useless.
Oh but wait, I can't forget Seung Yu's niece A Gang! She's the cutest thing ever... Loved the scene of her painting on Suk Joo's face! Haha.

Music (9.0):
The music was very good and also very typical of the Sageuk's I've scene with the mix of full orchestral and then a few male sung ballads and maybe some female singing throw in... I times I felt the main theme was played waaay tooo muuuch, but there was also this one haunting orchestral song with female bg vocals that gave me the chills. A good soundtrack, but not on my list of downloads.

Rewatch Value (8.0):
I will most definitely NOT be rewatching episodes 8-13 unless forced to watch the whole thing with a sibling or friend and if you don't understand why, go read my rant up in the story section. But the first 5-6 episodes, where our character relationships are being established were a joy to watch and will probably be on the top of my rewatch list. The last half of the drama was completed by yours truly in a blink (a day or two okay, give me three) and were very well done, but it is at times tearjerking enough that I don't think I'll be able to rewatch it as much as I would that first quarter of the drama.

Overall ( 9.0):
I've had this on my watchlist for ages and now that I've finally got around to finishing it, I can honestly say it wasn't a waste of time and I fully enjoyed myself. What a powerful love story!
For anyone who's watched the first few episodes, I also hope you caught my reference in the very first sentence of the review. Shame on you if you didn't.
If you are not a fan of Sageuks, I don't know how well this will resonate with you, but I've got such dramas as Empress Ki under my belt so this was a fairly easy and very pleasing undertaking for me.
P.S. I don't want to go through and fix my name spelling inconsistencies so figure it out yourselves.
P.P.S. I don't want to discourage anyone from watching this, so this is post scriptum, but I do feel like I'm being optimistic with this drama mainly because I didn't love it as much as I thought I would after reading some really good reviews of it and it didn't leave me half as a mess or in love as some other dramas (Empress Ki, Queen In Hyun's Man, etc). But it still deserves the 9 I guess. Maybe 8.875...
P.P.P.S. Is this my longest review yet? Maybe. It's like over 1200, almost 1300 words long. Here's to watching dramas when I should be writing essays and then going and writing drama reviews that are longer than my essay needs to be!