I give the buying experience 5 stars.
The DVD quality is very good. I feel this is important to know because sometimes there are multiple versions of South Korean DVD sets, and sometimes the production is not that great. The subtitles are inconsistent (too fast), and the image compression is too much to fit more episodes on a disc. That is not the case here.
The series I give 5 stars.
The series is well written and the acting is excellent.
First first episode is rough to watch. A clique of high school students tortures students they they consider lesser than them. The torture is psychological, emotional, and physical. There are beatings, and injuries using a hot curling iron. Moon Dong-eun is the protagonist. She suffers burns over much of body that affects her every day of her life. It is rough to watch. However, it is needed to set up the revenge against these students, an entitled wealthy narcissistic sociopath projected by her mother and influence, her equally well off narcissistic sociopath boy friend, and their three less well off minions. There is a hierarchy. As revenge goes, it is intricate, and well planned. Unlike a other revenge films, she never actually harms them. Rather she takes advantage of their flaws and the harm is self inflicted. She seems to show mercy to some of the minions, or is it a tactic to get the group to turn on one another? Along the way, she finds many allies. She has a positive influence on those around her.
The story is written so that everything is neatly addressed by episode 16. Excellent writing.
It is dubbed in English as an option, but I prefer to read the subtitle and her the actor's voice. However, the dubbing is well done. For more on the series, I encourage reading the Wikipedia entry, although if you are looking for the DVD, chances are pretty good you've watched it already. I watched this series five times over the past couple years on Netflix before deciding to buy the DVD set.
I hope this is helpful.