As a former generator repair technician, I'll take Onan, Kohler, and Caterpillar over Generac any day of the week. The quality in materials, construction and workmanship, was self evident.
To me, Generac was the type of equipment you threw out when it died. Repairs were difficult due to sealed non interchangable parts, engines that ran at 3600 rpm instead of 1800 or 1200 rpm, and a general make it cheap feel to the machines.
Obviously, these are just my opinions, based on my repair experiences, not your selling requirements.
Larry C