Great Value Ranch Corn Chips are superior to Cool Ranch Doritos. Actually, quite a bit of GV stuff is as good if not better than the name brand they are knocking off. Not all of it, though.
Kirkland Hotdogs are superior to Ballpark (but I mean, that's incredibly easy since ballparks suck) and I think are more comparable to a Nathan's or Hebrew National; although those last two are still better than Costco's signature dog.
Clover Valley (Dollar General brand) has the best fig newtons and cake snacks around. Way more flavorful and moist than the name brands Hostess or Little Debbie. Also their pop tarts.
Kirkland Signature products in general are just as good or better than the name brands because they usually are the name brand stuff.
Their batteries are Duracell, their bagged coffee is roasted by Starbucks, their diapers are Huggies, their canned tuna is Bumblebee, etc.
Kirkland hot dogs are an oddity, though. They used to be Hebrew National, but they got too expensive to be selling for 1.50 at the food court, so Costco bought an old Hebrew National meat plant in California and makes their own hot dogs now.