This post is part of our Battle of the Brands feature. Let us know which brand you prefer, and watch out for more Battle of the Brands posts.

A portfolio manager once said, "If a nuclear explosion hit my city and I had to pick one place to hole-up for a couple of years until all was calm, I would want to be at a Costco store. It has everything any human being could ever want or need." Well, I don't know if I could spend a couple of years in a Costco store, but no problem with a couple of hours!

Sam's Club, a division of Wal-Mart Stores Inc. (NYSE: WMT) versus Costco Wholesale Corp. (NASDAQ: COST): they have collectively changed the way people shop. The differences are profound between the two, yet conceptually they are very similar. Both "warehouse" concepts sell in bulk fashion. If you're looking for a small jar of Grey Poupon mustard, forget either of these two warehouse stores. But, if you want two side-by-side 16-ounce jars of Grey Poupon, enough to satisfy a football team, then you have come to the right place.

As similar as these two are, the differences do exist. Costco offers tremendous prices to its customers (club members) and quality. Costco has figured out the consumer will come in with a set list of items to be purchased, only to be enticed to expand that list as they walk the store. Strategically placed "special" items, or Costco employees serving out free samples of delicious food and drink items not normally found on the customer's list. It's brilliant marketing: on-site demonstrations and/or sampling of the product. "An impulse purchase" is the expression I have used many, many times as I've explained to my wife why I bought this or that.