I guess I'm gonna' have to disagree with some of this. As an authorised Generac service dealer for many years, I saw quite a bit of Generac product and yes.....there was some pretty bad stuff, but most of it happened when Generac put their alternators onto motors by Tecumseh and Briggs. The "real" Generac OHV motors were pretty good. They were easy to start, ran well, were full pressure lube with filters and with even a minimum of maintenance ran for a long time without trouble. The hardest part of being a service dealer was getting tech support and parts. Generac's portable division was sold to Briggs, and all we saw after that was portable generators with Briggs engines.....pretty crappy stuff in the smaller sizes, but at least parts were available.
I guess the downside today for me to use a "real" Generac motor would be service support and parts supply. I'm not even sure if OEM parts are available any more.