I have been pondering about this exact same question for a long time now.
and there are lots of ways to look at it..
it can be compared to OLD vs NEW in a way.
with the amateurish look ... you get the authentic "i am a porn surfer like you" feeling
with the new top end designs web 2.0... you get the "this is a savvy site like you are" to a surfer. which i would say are more likely to impress the younger generations
so it all depends who you cater for I would say...
personally I have been working on a lot of sites that have that new web 2.0 look... but then again the old i-made-this-myself look works as time has proven..
but recently I have learned the following
* the user DON'T want to find anything.. it should all be right there for them to click on... fewer clicks to EXACTLY what the user wants is better
* a few silly pictures or video with a crappy description WONT arouse the user into buying... you have to SELL the porn to them... ( this ain't 1996 any more)
* seo is important but don't serve pages made for robots because that wont sell
let your users stand before SEO bots but don't leave them out of the picture.
perhaps some things to consider irrelevant to the new vs old look