I am a member of both Costco and Sam’s. You go to Costco for the weirder food stuff that is very good and high quality, but if you want bulk of the popular brands of stuff, you go to Sam’s. Sam’s is also across the board cheaper on most things. Costco has more and higher quality home goods, sporting goods, outside stuff for summer.
I also like Sam’s because it’s less stressful to go through, unlike Costco.
Costco gas is great, but only when the lines are short. My time and stress level is too valuable to wait in a 20-car deep line just to get gas.