Boku no Shiranai Kanojo no Kao

All you need to do is to search "I will protect you" on Fakku to understand the notability of this H-manga. I don't know how much it ranks but this is arguably one of the most hated Netorare manga out there. For that alone, it's worth a peek if you can stomach plots centered around a childhood friend being raped and stolen away and then being re-united but the relationship has long been destroyed. What makes this really different from other Netorare is that this contains a strong female, a Shinji-like pacifist character, a sort of tradition gone crazy plot and ultimately an ending that is more realrape than the fantasy reality common to rape hentai. The cons though are still standard hentai fare: the female gets easily blackmailed, the villains are mostly standard evil bullies and a fat man with one notable character who at the ending gave an ambiguous unexplained smile and as with great macabre endings, the best audience are those who hate it and they tend to not praise the works they hate.