Yeah, I agree with you, my mid price Briggs powered unit has a General Pump I think--it is 3GPM at 2500PSI. It runs great still after 3 years now and I have used it a bunch. When this unit is gone though I am going to do what I should have done--get the big one! I will get the Honda engine and a big CAT pump. For the occasional user it may not be needed but pressure washers are like FEL's, the more you use them the more things you figure out to do with them. In all fairness though, the Briggs is running strong and the pump is doing fine. I think it needs a new gasket set. Our water here has a lot of minerals too.
You can, to a degree, increase GPM by lowering the pressure since I think most units have a pressure control adjusting valve. While my unit claims 3GPM at 2500, I set the pressure at 1500 and I figure it flows quite a bit more water. I added a pressure guage--designed for pressure washers and it is useful. J