I guess it's that I like the idea of authenticity
If you like authenticity then the porn industry is one of the last places to look for it.
I like porn that shows recognisable human emotions and moods, like desire, playfulness, pleasure etc.
When I watch porn the majority of the emotions I'm witnessing are arguably completely fabricated.
I've always thought of Hentai as being a more extreme version of artificially "enhanced" pornstars,
Seriously? At least you said "more extreme", which leaves the debate open that "real" porn stars are still "artificially enhanced", many to the level of "extreme" as well.
I don't like artificial enhancements because they somehow make everything look inauthentic and, well, dull.
While it is difficult to nail down a real percentage, it's arguable that the majority of "real" porn stars are "artificially enhanced", inauthentic, fake emotions and are otherwise, well, dull.
You're all certainly entitled to your opinion and I expect a slamming from the lemmings (and others) but I find it hypocritical to speak of "real" porn stars and use words like authentic.
To answer the OP's post, I'm not so into the cartoon type of Hentai but I'm finding the 3D Hentai that is out these days to be rather stimulating. It's a big turn on for me to see enhanced pornagraphic images, while clearly fake are otherwise not too far off from modern "enhanced" and "inauthentic", augmented porn stars of the day. Big breasted woman, with their heaving mams taking large shafts and copious loads from other humans or aliens alike... yeah it's a turn on (for me).
While I do prefer the real deal I find myself getting bored with it a lot and it's good to have some variety in my porn browsing.
J