Rainbow vacuum cleaners are so ridiculous.  My parents let themselves be conned into buying one of those.  I remember the sales person leaving the vacuum with us on a Friday to test out for the weekend.  I was like, "Why are we going to test it out?  It's $1300.  We're not going to buy it.  Even if it was wasn't an unbelievable rip off, we can't afford a $1300 vacuum."  Then I remember coming home from school on Tuesday and asking why the vacuum was still there . . . I thought we only had it until Monday, and my Mom said she decided to buy it.  I was only fifteen at the time and I remember actually feeling almost ashamed.  I couldn't believe that my parents could have made such an astronomically stupid decision.  You gotta understand how poor they were.  I mean, we're talking about a single-income family (~$40k/year) with up to ten kids at the home at any given time.  I could figure it out exactly, but when we got the vacuum it was probably around 8 or 9 kids.  And my parents didn't take any government assistance.  No food stamps.  No Medicaid.  I mean, we got things like free lunch at school, but none of the big ones.  We struggled.
But aside from them being outrageously priced, they are a pain in the ass to use.  You have to drag around this ridiculous rolling cylinder behind you that is filled with water.  Then, after you vacuum, you have a cylinder filled with a disgusting water/dirt mixture.  Shardian nailed it already.  He's got this $1300 vacuum that "works great", which he deliberately avoids using.  That sums up the Rainbow vacuuming experience.  And whether you paid $20 for it or $1300 for it, either way it just sits in a closet unused because who can be bothered to use it as anything but a last resort?