Have used various incarnations of this cleaner for several years. This model is a bit fiddly to assemble, but as you're only doing it once it's manageable. Having in the past had 3 Golden Retrievers and all the muck that goes with them at times, this machine is invaluable. The first time user will be amazed at the colour of the water as it's sucked up! One thing that has improved with these is the power of the suction has increased markedly - probably a more powerful / efficient motor. You don't have to use shampoo, more often than not I use just warm water, just as effective and add shampoo just for the stubborn areas.
Every carpeted home should have one.