Here in SA the Hoover Aquamaster was the first domestic carpet machine offered, using Exhaust air from the vac motor to pressurize a tank that then sent liquid to a nozzle, This was followed up by the aqua jet which used a small pump. Electrolux was quick to follow suit and then the Bissell big clean green machine was launched here. I have one of those. They are great for cleaning furniture and cars but for carpets, too much work.
We have a Hoover V2 for that, Recently its been giving some issues so I have had to rely on the bissell, I also have access to a few industrial units like the from machines like the Mytee speedster all the way to a truck mount its to much work to get them out to use most of the time. So I have just used the bissel and last week I got the V2 working again, what a difference, The carpet looks cleaner.
The upright machines just make life allot easier