My brother and his family, and my wife's sister and her family both use Generacs and have had no issues with them. I worked for several years for the guy who built our house, and when his customers wanted generators, they were always Generac, too, and I never heard of any of them having problems either.
Throughout the 16 years we've been in our house, the power has had a tendency to fail at the drop of a hat, so we finally bought one for ourselves earlier this spring and are waiting on it now. It didn't ship until July, and the dealer's installation crew was backed up until October.