This was not about the OP looking for a handy lightweight for doing the odd spot job in someones attic .
He is looking for a primary use extractor to start a business .
one 6.6 is not the same a s two 5.7s so don't lump them together .
One 6.6 is 25ft machine ... two good 5.7s like the electros ca be used at 70ft ...or will give vastly better performance at 25ft compared to a 6.6.
I started out with a square extracta single vac machine ( at least it had heat ) leaving it outside each room i did ... i could even carry it upstairs in my arms . But its a far less efficient way of working than leaving a good heated twinvac in one place and reaching around to several rooms with a longer hose . also i now get better drying and productivity in general even at close range ...
All these cub heads talk the same cleantalk language ... ' its so light weight '... ' punches above its weight ' etc
Iv seen people like russ chadd used to talk like that at one time ... ' the jag was the future of machine performance ' etc then he tried an Enforcer and a high spec Alltec express and was blown away by the performance , heat and build quality .
https://www.youtube.com/watch?v=wQTQjPKXkvI