With my experience, different Costco stores have different experience. The closest store to me is small and messy, and SKUs are too limited so I had to go to other supermarkets after checkout. However, another store (10km away) is neat and clean. Although crowded, the checkout process is very smooth.
If the Costco you visited made you disappointed, I'd suggest to refund the membership. We're paying to shop in Costco, and it's fair to expect good shopping experience.