I had my spouse, who crys often at movies, watch it with me. I gave them fair waning that it was very sad and apparently very good. She agreed, and was also "I'm never watching that again". She enjoyed it. Can confirm, brutal and great. But like other amazing sad war movies like Schindler's List, I'm not going to watch it for fun.

Actually that's a good way to think of it, compress SL into a anime length movie and you have the emotional hit of Grave.