I will say that Kirkland >>>> Members Mark
Being a city kid. I don't shop either store myself, but purchase a lot of those two brands at the local bodega marts for a slightly inflated price.
I have learned Kirkland is a quality brand, while Members Mark has more of that generic store brand feel to it. So I would support Costco as well.
Right, even knock off Kirkland stuff is still better than real Walmart stuff.