This is probably one of the better Korean manhwas I've ever read. In my opinion, it's better than the average shoujo manga plot(coughYuu Watase, anyone?*cough)
The political aspect of the story could be a potential turn off to readers who dislike complicated stuff, but I'd say the relationship developing between Shin and Chae-Gyeoung is well worth it.
Sure, there are a few moments when it becomes too... "chibi" grotesque, but mostly, the art's quite good for a Korean artist(it's not as clearcut as that of manga, but it's still pretty in its own right). I don't really think there's a moment when you, as the reader, could point and say, "Yah. I don't think I would do that. That's unrealistic."
The characters are very human and they make lots of mistakes(and by a lot, I mean LOTS). Sometimes it does a get a little side-tracked(with the whole bits about the eunuch and such) and it does get a little irritating, but overall, I'd say the story was mostly enjoyable.
On another note, I'd say watching the drama before reading the manga is probably better. It does a pretty good job of summarizing the plot(but of course it'll have a few different twists not in the manga), and it's a really good prelude to the story.(By which I mean it'll help you to recognize some of the things about to happen when you're reading the manga, but only enough so that not everything becomes something to be expected).
The drama's called Princess Hours in english, but Goong in chinese/korean. (Look it up on wiki-d).
BTW. Here's my last two cents: Agh, I detest Yul. Ugh. All my friends love Yul ever since the drama, but I still worship Shin(and the fan-coupling ShinxChaeGyeoung.)
Yul keeps killing all the good momentsT___T He kills everything.(And ahaha, Shin is so funny. So is CG. She's flipping cute AND scary. which is very wierd.)
Yeah, I'm rambling now because I'm still high off my Goong-rush. I've read all the chaps. up to 95 so far in three days, and it must be seriously affecting my ability to review.