We have memberships to both Costco and Sam's - mainly because we moved and there's Sam's right next door.
The Sam's Club experience is the opposite of everything we hate about trips to Costco. No matter what time of week/day it is, it's never swarming with people who have seemingly never shopped in a public place, it's easy to find parking, the staff is friendly and they have some great Gluten Free options. :)
Now we visit nearly every weekend.