The add on seats don't seem to be any kind of an economic deal for just air.
According to my wife, 'the water is where it's at'. She has already told me
that when we get our next house she wants one, so I too will watch the
answers closely as I will be doing one in the next couple of months myself!

Jay

They all have models that use heated water. A side benefit of the Toto
is that it also deodorizes dunno about the others. If you have a lot of
guests that will become an function that you'll wonder how you lived
without. An additional benefit is that your toilet paper use will drop
dramatically.
When I was in Japan my relatives had one that had a humongous remote
(the Totos have a remote too but it's small) there was an entire bank
of buttons that were just for women. I mean like 20 buttons: different
patterns, oscillations, drying air. I'm not sure if it has arrived here
yet.
I installed the Toto myself, very simple, replaced the previous seat
and only needed an GFCI outlet. If you install one make sure you don't
"lose" your wife in there. ;).
Richard