There's something almost philosophical about the Costco checkout line. All that bulk, all that value, all that existential math. You've just spent a few hundred dollars on paper towels, coffee beans, and a kayak, and the cashier asks, "Would you like to upgrade your membership to Executive?" The main difference between Executive and Gold Star is that for $130 ($65 more than the Gold Star membership) a year, the deal is 2% cash back on most purchases, capped at $1,250.
If you're a fan of the flat-rate card, and you should be (in my opinion), then you should start thinking about which card in this space is going to give you the most bang for your buck. For this Redditor, finding the best 2% unlimited cash back credit card is at the top of their list. The good news is that they have some choices, with each card in space offering something slightly different.