Have not been to a Sam's, and online checking indicates the prices are not better (and just a hair worse) that Costco for most things. Have a friend who has both cards, and he prefers Costco by far to Sams. He says Sams has the feel of a big Walmart, along with the stereotype of the clientele. He only has Sams because it is closer to his home and his wife doesn't like the drive. Also the Costco closest to his house is a bit of a zoo for parking.
Still may float thru a Sams just to see for myself, but doubt there will be anything enticing.