I've had all 3 within the past year, and honestly I don't get the obsession with Shake Shack. I'm going to chalk that up to east coast bias, just as with sports and seemingly everything else in life.
I'm a west-coaster for life so I'm completely and utterly biased, but give me a double double, animal friends, and a Neapolitan shake over anything from Shake Shack or Five Guys.