Shake Shack vs McDonald's – which is the better burger?

Shake Shack started as a small hot dog stand in Manhattan in 2001 – now its burgers and shakes can be found all over the world. What's more, the rise of Shake Shack comes as the original home of the burger is on the slide. On Friday, McDonald's reported a 15% fall in global annual profits. New Yorkers seem to find value (if not necessarily taste) in both brands, as the Guardian's Rupert Neate found out…