Sam’s has the most stores nationwide, Costco is second, but I don’t believe there are anywhere near as many BJ’s stores nationwide. Where I live, we only have Sam’s and BJ’s, but more people go to Sam’s even though the prices, selection and coupon policy are better at BJ’s. I guess the people are just more familiar with Sam’s.
being from California, i have been a Costco member for over 20 years... back when i became a member, we had Costco and Price Club as our options...
right now i am in North Carolina, and in our town we have Sam's Club and a brand new BJ's... i have never been to Sam's Club... but in my opinion, BJ's does not compare with Costco... Costco has a better meat department, bakery, prepared foods selection... more produce (maybe that is because i am in California when i shop Costco?)...
the one thing BJ's does offer that Costco doesn't is a deli--where you can buy meats and cheeses that are sliced right then and there for you...
in any case, Costco blew it... in the words of Beyonce' in Irreplaceable:
you must not know 'bout me, you must not know 'bout me... i can have another you by tomorrow so don't you ever for a second get to thinkin' you're irreplaceable...