Your quote - Any opinions on the above would be appreciated
They will all clean carpets, no problem.
Your quote - It would appear that you dont get lots of power with little weight!
Dont understand how you get to that.
The Scorpion, and I have one so can speak freely, has 3-3 stage vacuum motors and a 500psi pump, and uses 2" hoses. Thats as much power you going to get from 2 mains cables. Add a external heater (3rd main cable)and you have a brilliant machine.