Apple has two different products in the top five. But the number-one brand in America wasn't created by Steve Jobs.
Although companies spend billions each year to try to make their brands resonate with consumers, few ever end up with truly fanatic customers. But the perks are huge for those who do.
Loyal customers consistently come back to buy more, they're more willing to stay despite increases in price and they become strong advocates for the brand in their own social circles and online.
Brand Keys, a research firm devoted to consumer behavior metrics, recently updated its 2011 Customer Loyalty Engagement Index, which looks at 528 big brands in 79 categories -- from smartphones to allergy medicines. Through a combination of psychological assessments and statistical analyses of customers, Brand Keys determined how much brands exceed what consumers expect, and how loyal they will be down the road. Here are the 20 brands with the most loyal customers.