I saw this movie before i read the book and i have to say it was really really good.
At first i was a little bit annoyed about the half English - half German speaking mother, but when it came up she had an American heritage it wasn't so bad after all.
The characters in the movie were lovely and you could empathize with them in many ways. The main characters (Phi, Glass and Nicholas) were played very well. I loved the cut-scenes, which came up to show the emotions of Phil - and the music was also carefully chosen (Down by the River by Milky Chance).
The movie gives you a feel good vibe...lot of great pictures. The scenes from the childhood in a very nostalgic way.
The fact that it was a homosexual love story was, in my opinion, not the main setting of the movie. The homosexual setting was like every heterosexual setting in any other movie. It just was there. Was played beautifully. I recommend it to everyone! A high quality German/Austrian "young modern scenes" movie...wonderful and just as good as any American film.