There are two options in my area for a rented carpet cleaner: Rug Doctor and Bissell.

Which is better?
Do both use hot tap water?
Must you use the "name" brand cleaning products in them? I have some leftover cleaner purchased a couple of years ago that I used with a friend's carpet cleaner.
Which is better/easier for stairs?
Can one clean upholstery with these cleaners?

It will be a few weeks before we're ready to do this large task throughout the house, but I thought about it this morning. I have an old "Big Green Clean Machine" and have borrowed a friend's Hoover. I have no interest in purchasing a machine at this time. We're starting to downsize and don't want more stuff.