Have both machines, the Powerflight & Ninja (400psi, but no steam-mate)
Perfomance wise I would take the powerflight, especially for the heat it produces, steam-like once the vacuums have warmed up or fill with warm/hot for almost instant steam.
But for usability I would have the Ninja.
The powerflight has its issues with the size & weight when loading/unloading or dragging up steps.
The build quality, the Ninja feels alot more solid.
And filling & emptying the water & waste tanks, although I have adapted mine to make life easier.