I have to put myself firmly in the 'I prefer JAV' camp, and that is, bizarre as it may sound, is partly due to the censorship laws in Japan.
Let me explain.
I am not, nor have I ever been interested in sex, and while I love the female form I am not interested in seeing it naked, it's the way I'm wired. I have a very heavy underwear fetish, fullback, panelled, synthetic fabric panties specifically. I've been obsessed with them for as long as I can remember and am quite comfortable with this.
Japan seems to have a similar love and understanding of this kink. As such here's a larger emphasis on panties\pantsu\panchira in JAV, even in movies that aren't specifically centred on this kink and a lot of the girls are in underwear for a long time before getting 'down to business'. I suspect this is a: Due to the panty culture mentioned above, and b: Due to the censorship laws, get as much action as possible out of a scene while the girl is still covered.
Given the choice between straight up JAV and Softcore\Idol material the latter is my preference, for the reasons above. Studios such as Spice often feature beautiful lasses in stunning underwear, playing with vibrators and this stuff is like digital crack to me. You can't find anything comparable on the Western market.
I also find Western porn is just about getting naked as soon as possible and straight into the fucking. Not interested, it generally bores me, plus the artificially enhanced, tattooed, pierced look that has crept into Western porn over the last few years is a major turn off. I much prefer the natural look of the majority of JAV stars.
tl;dr JAV caters to my kink more effectively than anything else.