If you love bloody fight scenes, bad language and a plethora of bad guys, you'll probably enjoy this.

What I liked:
-The dynamic between the two male leads. I liked watching their friendship/camaraderie build. The scene in the barbeque restaurant when they were just getting acquainted as good, and I laughed at Do Hwan's character switching to honorifics when he realized he was the younger of the two.
-The workout exercising scenes. Superficial, I know.
-Woo Do Hwan. I felt that he did a good job with this part. He was being forced into something to stay alive, to a certain degree. I liked how he never lost that side of gentleness that he had. The last episode when he sees his mom, very touching. And don't get me started on his deep voice!
-Si Won. I enjoy him as an actor, and in this role he wasn't his quirky/odd self.

What I didn't care for:
-I felt that a lot of the fights were very over the top and unrealistic. I mean, you practically get beat to a bloody pulp, but then a couple of scenes later you're fine. And the main bad guy, when he was fighting the ML at the end? The guy was in his 50's to begin with. He's fighting against a trained fighter, but almost gets the better of the ML?
-The disappearing girlfriend. What happened?
-Bloody, bloody, bloody. I know, they're fighting, but wow!
-The cursing. Personal pet peeve of mine.

My bottom line would be that if you are totally into action shows, give this a try.