Hi KuroKat, welcome to the message boards.
To be a little bit blunt, knowing my opinion, or anyone else's for that matter, about hentai and porn more generally, probably isn't going to help you. As long as the media you're consuming is ethically produced, then what really matters is your opinion.
I hear you saying that you feel ashamed about it. Can you tell me a bit more about where those feelings are coming from? Have people in your life, like your friends, parents, peers, etc, expressed negative views about pornography?
Are porn and hentai something you want to be able to feel good about using, or something you'd rather not use?
We have some articles on our main site about porn, the first of which is still shiny and new! How about you read either or both of these, and come back and we can discuss?Making Sense of Sexual MediaLooking, Lusting and Learning: A Straightforward Look at Pornography