Both retailers are executing well lately, but one stock looks better than the other for the long term.Walmart (WMT 1.72%) and Dollar Tree (DLTR -1.70%) shares have both surged over the past year, standing out in a choppy economy with their value-focused retail models. Each company has delivered solid results for shareholders recently, but their investment cases rely on very different strengths. Walmart, the scaled and tech-driven retailer with supercenters, Sam's Club, and a fast-growing e-commerce platform ...