I waited a few months into our membership to review Sam's Club and I can safely give them the "Yay! I'm a fan" stamp of approval.
We have had a membership at Costco for years, but with just two of us in the house, it's hard to buy much there because of the sizes. My favorite things about Sam's Club are the availability of smaller portions. You can get a single gallon of milk as well as a six pack of the obscenely sized muffins rather than having to buy double. They have a huge selection of baked goods, meats, cheeses, and frozen foods. We have pretty much shifted our grocery shopping entirely to Sam's and fill in the gaps as needed at other stores such as Target.
The real winner, however, is the scan and go app. You can scan everything as you add it to your cart, pay via the app, and just check in with the receipt checker on your way out. They do have a ton of self-checkouts, but I still feel like the app saves me time.