Depends on the Generac. There smaller units come from a different line (that they acquired).
I have had an 80 KW Generac in operation since 2008 on my house. It's been trouble free. 90% of the maintenance is easily done (oil changes and coolant changes are trivial the way they installed the drains). Getting the "car" battery out when that needs to be replaced is a little challenging but not hard. The only real stupidity in the design is that the cooling fan belts are not installed behind one of the readily openable panels. You have to remove a dozen screws to get to it.
I put a Raspberry Pi monitoring box on mine because the alarm is a rather feeble sonalert that I can't hear unless I'm right next to the thing. The one warning is that the later controllers Generac has taken to encrypting the MODBUS port, so the open source monitors won't work. You'll be beholdedn to Generacs remote monitor service.