Seen it too, subtitled. "Masterpiece" is probably over the top a little, but I don't think any European viewer can really relate to the plot as it's rather weird premise of modern day Korean going through some sort of Crime & Punishment/Dickensian era inequalities and servitude but before I belittle the validity of subject - someone on another forum wrote that as a plot idea - it's not very far off from extreme spectrum of life among minorities (especially with illegal status) in today's UK so I'm just going to shut up and go with it.
The movie is weird enough to be interesting, in a "Talented Mr. Ripley" way, I'm glad I watched it, I'd recommend it to others, I will not buy a copy or keep it for later viewing, I'm sure many will feel compelled to shower it with rewards in months to come, but ultimately I'm not sure it's actually as clever and brilliant as people think it is.