Pros: A good, flowy read. A nice mix of everything, including action, drama, darkness, great art, humour, with original and realistic aspects in the storyline (Particularly with the true unglamourous side of war, from the violence and social status, to the sad fate and treatment of women who are the spoils of those wars. Yet while serious and realistic, it isn't overdone where it gets painfully gloomy) The manga also gets you thinking about life in general, as it can be quite thought provoking. If you enjoy snippets of Korean History, you will get that too.
And, for those who fancy it; there is a subtle romance story. And an unconventional one too, as it is not the usual "Boy meets girl, boy is strong, girl is dainty, boy saves girl, gush gush love" yada yada. Both characters are quite strong in their own right, and play their roles and personal goals. Overall felt like a partnership in many areas.
Cons: Sometimes battle scenes can be a bit too prolonged. Or, at least, might just cover too much space in pig pictures covering whole pages. At least a couple of volumes can be read within minutes because, well, there is just displays of fighting scenes and very minimal dialogue. I buy a book, an then I am done in a snap because of that.
Some parts will also feel a little bit too random/rushed, or have instances where the characters will be developed and announced as one thing, but then have a turn of being a bit OOC later on.
A con or a pro, it will depend on you: You will either think the ending a true plottwist, incredibly deep and unique, with a dash of "OMG Mindf**k".
Or, you will be disapointed in the ending. Either finding it a bit anti-climactic, or react with a solid facepalm.
I myself have mixed feelings about the ending. I was legitimately surprised, but at the same time...I would have definitely prefered another alternative, between the final meeting between the dubbed antagonist and the protaganist. I also wanted something more.
Anyhow -> Altogether, I do highly recommend this series. It's a quality Manhwah.