Buying a standby generator through Costco vs buying “direct” from Generator Supercenter

I’m in the market for a standby generator and I keep hearing about Generator Supercenter. In addition, I contacted Costco when I heard they offer standby generators, only to find out they more or less partner with Generator Supercenter who does all the installs etc etc

My question is, is there any benefit to buying “direct” from Generator Supercenter as opposed to buying through Costco? It’s my understanding that, with Costco, you end up with a gift card worth 10% of your purchase price. Is there any benefit to NOT doing it through Costco (if I were to choose one or the other?) Does Generator Supercenter charge different rates going through Costco or if you go direct with them?