I love the Green Machine. Great for pets (been there, done that), also
excellent for car upholstery, house upholstery. The stuff that comes
with it is Ok, but I like the stuff (cheaper) that you can get at the
grocery/hardware store with the rentals. Comes in a big red container
-- no idea what the brand is. I also have a small Bissel upright for
carpets as well. I need to get a bonnet buffer/scrubber one of these
days as well, as my old Hoover gave up the ghost a year ago, and I
haven't gotten around to replacing it.
Carpets on stairs take a real beating. I have replaced the stair
carpet before I've replaced the floor carpets.