The product (name-brand quartz) isn't the issue here...it's the local fabricator/installer who has the contract with that particular retailer. Review the contract as to who is responsible (retailer or fabricator) if things go awry.

Thank you. I am mostly interested if there is a cost savings at Costco.

Thanks. I get what you are saying.

Costco isn't going to endanger their brand by subbing work to hacks. They use their buying power to negotiate lower prices with manufacturers.

Did anyone find out the cost savings with costco vs home depot?

I don’t have the answer to that specific question. However, I can answer what our experience was as related to buying quartz from Home Depot. They use the same local (well-respected) manufacturer/installer that everyone else uses, but because we ordered it through Home Depot, we only had to pay a square foot charge, we did not have to buy the whole slab. So we only had to pay for half of the cost in effect. I do think that the stone company sent out their second rate installers, but they did an OK job.