I just wanted to point out that the US prices are pretty comparable to the Japanese prices. And after having lived in Japan for nearly a decade, I'll pay the price in a heartbeat. The previous occupants of our apartment left one in our apartment and it's one of the cheaper models (about $3-400 IIRC). It's still awesome and worth every cent. You could probably even justify it based on the reduction in toilet paper if you want to, but I don't even think of it. It's gotten to the point where when I go back to visit the UK or Canada, the lack of cleaning options is just disgusting in my mind.
Totally agree, I have a cold water replacement seat type of model, I can't justify getting my bathroom rewired when a $60 device is pretty close almost there. :)
My master bathroom toilet is right up against the closet my water heater is in, so the "cold" water is never that cold.
Edit: weird wording