McDonald's (NYSE:MCD) has been a dud in 2012, while Yum! Brands (NYSE:YUM) has continued to outperform, but with that run has come a premium multiple. 

So which stock is a better buy today: the cheaper, underperforming McDonald's or the rosier and more expensive Yum! Brands?

Mickey D's has a more sustainable long-term model than just about any company in this space, and has a low price-to-earnings ratio right now. In a world of short-termism, it's easy to forget that the best investment is measured in years, not quarters, and when you take a look at McDonald's long-term trend, investors are getting a bargain, making McDonald's the better buy today.

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.