Shares of Family Dollar (FDO.DL) rose today after solid third-quarter earnings. Sales were up 9% and comps rose early 3%. Despite the good numbers, Motley Fool analyst Jason Moser is reluctant to consider the stock. For one thing, retail giants such as Wal-Mart (WMT 3.98%) and Amazon.com (AMZN 3.97%) pose an ever-present threat. Moreover, Family Dollar is already facing direct competition from other discount retailers suhc as Big Lots (BIG) and Dollar Tree (DLTR 0.61%). For those reasons and more, Jason recommends investors avoid the stock.