Some excellent and well thought out replies there, but still this ever-present notion that a TM is something that you aspire to or that you only get when your diary is full. So I'll throw another controversial, but none-the-less true aspect of this onto the table in order to make a very important and often overlooked point.
Generally speaking (I'm picking my words very carefully) the horror stories that you hear almost everyday about people's last experience of a carpet cleaner are about people withe portable machines, tho I heard one lately about a TM. There must be a lot of them because the stories are everywhere and have been there for all of my 36 years in the industry. The fact is, people don't trust carpet cleaners! This industry has a terrible reputation which may well explain the popularity of Rug Doctors, Vax carpet cleaners and Vanish foam carpet cleaner, people must be thinking, 'I might as well do it myself,.'
People don't want to do it themselves, they just want it done by a professional comapny that will give them great service and a carpet that is super clean and dry in hours - not days. The problem is their perception of what they will actually get is the complete opposite of that and that tars ALL carpet cleaners with the same brush........