>are there hentais with story and not only sex scenes (or at least some context)?
>what are the best hentai plotwise?
pics mildly related
"Wain no Kachikan" (bizarrely translated as "sense of values wine") and "Teacher and Student" both by Fuuga are pretty good. The stories are similar but different enough.
Sweet Guy. It's a Korean manwha with a nerd MC gaining a power after an accident. He makes everyone he touch feel good that woman want to have sex with him (and guys starting to feel gay). Starts off with a lot of sexy time and plot takes a serious turn afterwards.
Michael Keikaku. Starts off with a playboy guy being turned into a girl due to some drug. Later gets involved in a conflict within her new school where the students are (unwillingly) trained and sold as sex slaves/wives.
One of the best gender bender stories in my opinion. Aside from the inevitable sex scenarios involving her new body, MC develops into accepting her new body and sometimes uses it to her advantage. She even becomes a mother at the end. My only gripe is that she chose a girl instead of a guy as her partner in the end.
Ring x Mama. Guy is a fan of women's wrestling and his landlady just happens to be his (retired) favorite wrestler. As with pro wrestling, stars make a comeback after 'retiring'. Anyway, he starts a relationship with her and becomes the manager of their stable.
As with Joji Manabe works, he uses the same formula for sex: harem where MC fucks all the female cast. There's a story behind everything but it's not heavy or dark.