This month ROC United (Restaurant Opportunities Centers United) released the National Diners' Guide 2012: A Consumers Guide on the Working Conditions of America's Restaurants (PDF), a guide that outlines how well employees are treated at 150 restaurants/chains around the country in regards to wages for tipped and non-tipped workers, whether there are paid sick days, and whether there are opportunities for advancement.
Out of the many burger chains rated, Five Guys and In-N-Out are rated the highest. Read the PDF for an explanation of the symbols, but to summarize: Five Guys earned the Gold prize for belonging to one of ROC's Restaurant Industry Roundtables, for giving paid sick days, and for having over 50% of their workers move up in position; In-N-Out earned the Silver prize for paying at least $9 and hour to non-tipped workers and for giving paid sick days.
I compiled other burger chains in this image.
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