The authors argue that positive employee relations effectively serves as an intangible and enduring asset, and may, therefore be a source of sustained competitive advantage at the firm level. They analise how the measures of firm-level performance are likely to be affected by highly positive firm-level employee relations. Focusing on publicly traded firms included in the "100 Best Companies to Work for in America" the authors empirically investigate whether positive employee relations is related to firm performance. The relative performance of these "Best Companies" is examined via comparisons to both companies in the broad market and a group of matched firms. The authors conclude that that companies on the 100 Best list enjoy not only stable and highly positive workforce attitudes, but also performance advantages over the broad market, and, in some cases, over the matched group.