I bought a lawn mower the other day from an engineer who fixes plant machinery etc, swears by the GX range as long as you don't over load it way with a rotovator or gennie application can as they don't like it and can blow a rod or something. In a pressure washer scenario this is never a problem as the engine dictates the output and not the other way round if you know what i mean. he did say that he really rates the loncin engines are these are almost carbon copies of the gx range, he swaps parts over as they are a fraction of the price.
there's a welknown pw manufacturer out there who use loncin and interpump and apparently these are really good!