Japanese latest toilets have a lot of functions. When you sit down on there, you don't feel cold on your butt, the seat is already warm (it's not the warmth of someone that used it before you!) and you feel comfortable. So you don't have to hate going to toilet during in cold winter. After you finish the thing, it will wash your anus with warm water. All you have to do is pushing a button. There are some models that have a drier and dry you after washing it, you don't even have to wipe your bum. Such types of toilet seats are in wide use here. The diffusion is almost 70%.
Let's go to a toilet of some big department stores in a big city if you wanna see the latest clean comfortable toilets. Toilet cover opens and music starts (to hide the noise when you are getting a wash) automatically when you come in, of course the seat is warmed up, you can wash and dry your bum after finishing, and when you stand up, it'll flush by itself. Moreover, the powder room beside the toilet might be so beautiful and you might feel you are a princess or something, lol. They are well designed.
Restrooms are a place that remind us dirty things, but there are restrooms that don't remind us such things and let us feel comfortable and maybe a little bit happy when we go there. I think it is the result of the efforts of Japanese people who are tidy, and such a toilet is one of the thing that we can be proud of in the world :P
By the way, of course there are toilets that aren't a latest one. Especially about Japanese style toilets, I heard it is kind a hard thing to use for foreigners. Firstly, the shape looks so strange for them, and they don't even know the front side. And secondly, they're not used to to squat down over the toilet. You'd better visit here before coming to Japan. There might be a chance that all seats you can use are Japanese style ones! lol