When you are the go to generator for every RV manufacturer in the USA your product will obviously gain more attention. Onan makes an RV generator second to none and although there are other generator manufacturers (Honda & Yamaha) they can not engineer a product that could dethrone the market dominator.
Our current rig is 7 years old and our Onan has over 700 hours of reliable service under it's belt. We simply change oil and filters yearly and she purrs along happily supplying 120Vac just as if we were plugged into shorepower. We add Stabil and an occasional bottle of Seafoam and even use whatever ethanol laced fuel is most economical with never an issue with carburation or fuel delivery.
Onan generators are designed to be used and many have several thousands of hours doing what they do best. The majority of issues come from severe under-usage, lack of general maintenance, and stale fuels that make a mess of the fuel delivery system. All are easily avoided but alas many owners don't have a clue. You would think when someone spends $4000 and above for such an item they would be diligent in it's upkeep.
For us Onan is the only way to go as we often camp in extreme temps and run our AC units or a couple of portable heaters to keep comfortable. Properly installed they are moderately quiet and easily perform their job meeting the demands of those who want to power their entire rig with a simple press of a single button from the comfort of their rig's interior. Suffice to say, DW wouldn't even consider camping without our Onan fully operational, no sweat as I spend less than an hour per year on maintenance.