Thing is you don't seem to be able to buy a machine with twin 6.6 vacs 500 psi pump and a heater due to the electrical load, so maybe the twin lambs would be better option?
Alltec evolution got round that by fitting a smaller inline on each cord and combining the two , not sure if there are using the 6.6 these days . Ashbys have a twin 6.6 enforcer with an immersion heater on a third cord .
In reality you could run the powerflite with two 6.6 one one cord ... its just they can sell you one like that .
Powerflites are ok im sure , i would go for the twin vac , also look at configuring an airflex custom/storm on cleansmart site ... look at alltec machines like the elite , and ashbys enforcer if in budget