It's a good thing you created this thread at the same time with the Phungsan Dog one. The two movies have a few things in common: the lonely hero; the senseless cruelty of people with power - be it within the political world or the organized criminality (there isn't such a huge difference between the two worlds, after all); the revenge theme.
BUT! The Man from Nowhere is extraordinarily touching. I love the sharp contrast between the scenes of Won Bin with the kid and the action ones. And while I write this, I think I finally realized what I missed in Phungsan Dog: moments of true respite. Ahjussi gives us the time to witness the bond which is created between him and the little girl and their moments together are very sweet. Even the bad guys have their comic moments: their crazyness is such, it gives out the impression of a theatrical movie.
PD doesn't. I never took a long breath throughout the whole film, because it was all so agonizing and dark and cruel. Even the kiss took place in those conditions.
But I have written a review about The Man from Nowhere a long time ago, so I won't bore you further with another one here. :)