Not really knowing anything about this movie other than the summary, I went into watching it without any expectation or prejudice. While the subject matter certainly could be interesting, the storyline and directing really left much to be desired. I even think the character played by Marcel Schlutt (who is a total hottie) has some acting potential, but that is unfortunately not exploited by the film's director. There are too many awkward moments in which nothing is happening, and the characters are quite wooden and quite lackluster. Unlike the other post here, I felt that the English translations, while at times good for colloquialisms, left a bit to be desired.
On the other hand, I did think the idea of using real sex scenes is a novel concept, and certainly made for more convincing 'acting'. I wish the reality of the sex moments could have been translated to other parts of the film (or at least make the sex scenes longer :) It certainly doesn't come across as a 'porn film' other than the quality of the (non sexual) acting at times.
I can't say I recommend this as a need to watch, but if you just can't find anything else to put in your netflix cue, it might be entertaining, at least from certain angles.