Christopher- Electromatik: I like your Mom's rule you learned from her about not wearing shoes in the house! I don't know if I would necessarily agree with her about it being the worst thing you can do for carpet, but it's one less source of dirt to get tracked in & embedded in carpets to have to deep-clean out later on. Plus, if you're a busy person with work, family & friends, like most people these days, less dirt = less time vacuuming. And as much as I like vacuuming, less housework is a GOOD thing in my books! lol
Back when I was a kid, in the 1980's here in Ontario, Canada, I remember seeing the blue Easy Off canister extractors with the power brush most often. There was also another brand called Nautavac, which is still around today but they were less commonly seen. Then, in the 1990's, we stopped seeing the Easy Off extractors & it seems the red Rug Doctor Mighty Pro upright extractors replaced them. That's all I ever see in grocery stores to this day.
Erik: I wouldn't worry about buying the Rug Doctor R-40, if your concern is that RugDoctor says not to buy them because they are stolen rental units (which is what I have heard the explanation is for them saying not to buy the red ones). That one looks pretty old, probably from when they first started out....Chances are pretty good that after a certain age, they sold it off & replaced it with new stock, so their rental equipment lineup remains in good shape & up-to-date for customers. Easy Off had a history of selling off used machines when they were around, so I bet RugDoctor probably does the same. I would bet good money it has probably seen at least a couple of owners, & if this IS on Ebay, of course you would have no way of knowing it's true history....even the seller probably doesn't know

. Having said that, it wouldn't hurt to call RugDoctor & innocently ask if parts are still available for the R-40, so you aren't stuck if it breaks down.
Rob