In my area, both Sam's Club and Costco seem pretty balanced in regards to computer and electronics offerings. For tire services, both also seem very similar. For food, Costco seems to be a bit ahead of Sam's Club in their offerings. However, I have memberships to both warehouses and tend not to favor one over the other - except for the fact that the Costco warehouse is only about 4 miles from my house and Sam's Club is about 12 miles from my house.