Ah, so here we are talking about "dolls".
I'll honestly admit that Japan has a huge and unique variety of dolls that you probably wont find elsewhere. Especially anime oriented ones...
If you were to pick up a Japanese Hobby Magazine such as Hobby Japan or Dengeki Hobby magazine the pages in the back are usually all dolls, figures oriented.
The dolls/figures would go anywhere from simple figures that of super hero series to a 1/1 (as in real human size that the char is profiled for) scale of chars such as Ayanami Rei from Eva. and etc. and as you mentioned some XXX, hentai themed figures...
Honestly the 1/1 scale idea creeps me out even as an otaku. Thats going a bit far in my opinion. The XXX/hentai figures, I dont know what they're thinking.
Sure I have a few figures myself, the NORMAL ones. Like Mahoro-san from Mahoromatic, Anita from R.O.D, and a couple others.
To me these are just collectibles that I like to dispaly, nothing more. Thats what most dolls/figures are for. To either display or play with.