In its ranking of firms on the basis of customer service, BusinessWeek (March 2, 2009) collaborated with J.D. Power & Associates (a global marketing information firm that conducts independent surveys of customer satisfaction; BusinessWeek and J.D. Power are both owned by McGraw-Hill Companies) to develop a list of the top companies. The ranking was based in part on ratings by J.D. Power and also by a survey of 5,000 readers of Business-Week. The top 10 firms are listed in order:
1. Amazon.com
2. USAA, an insurance firm for military personnel
3. Jaguar
4. Lexus
5. The Ritz-Carlton
6. Publix Supermarkets
7. Zappos.com, online retail
8. Hewlett-Packard
9. T. Rowe Price, brokerage
10. Ace Hardware

Required
Which of the above firms would you classify as a cost leader and which as a differentiator, and why?