I used to be a member of BJ's Wholesale Club (NYSE:BJ), but that was years ago. Now I'm a loyal Costco (NASDAQ:COST) patron. Being a retail enthusiast, it's amazing to me that I've never even set foot in Wal-Mart's (NYSE:WMT) Sam's Club, which happens to be the leading wholesale club operator in the U.S.

While BJ's (153 wholesale clubs) and Sam's Club (530 locations) seem to have the U.S. cornered, Costco has expanded its 329-store domestic base abroad. Costco has locations in Canada, the U.K., Korea, Taiwan, Japan, and Mexico, putting it at a competitive international advantage against its domestic competitors.

BJ's, which started its wholesale club concept in New England in 1984, may not operate internationally, but it has refined its domestic operations over the years. Merchandising and operational improvements helped push third-quarter earnings of $0.33 per share above the analysts' consensus estimate of $0.31 per share and 14% ahead of last year's earnings of $0.29 per share.

The company's net sales increased nearly 10% in the quarter, and its same-store sales grew an impressive 6.1%. In addition to operating 153 BJ's Wholesale Club locations, the company also manages 80 gas stations in 16 states. These petrol pumps contributed about 0.4% to the 6.1% same-store sales gain and a respectable 1.1% to the 10% net sales growth. Enhancing member benefits and offerings has been a successful component in the company's merchandising and operating strategy.

The one competitive advantage BJ's has always had over Costco is the utilization of an express line. How many times have you made your way through Costco to buy an item or two and then had to wait on line with people with full carts? I've made the express line suggestion many times but have become resigned to the fact that I will fill up my cart and spend more than $100 like the other "good" boys and girls.

With retail trends seemingly perkier than in recent years, it's probably a good time to think about loading up on quality specialty retailers. With the fourth quarter (or, as retailers affectionately call it, "money time") in play, a sound investment portfolio will have a mix of quality specialty retailers including BJ's, Costco, Wal-Mart, and Target (NYSE:TGT).

Costco is a Motley Fool Stock Advisor recommendation.

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Fool contributor Phil Wohl spent more than 12 years on Wall Street and owns shares of Costco.