I, for one, congratulate the senator from Kentucky on ascending from "Mitch McConnell Turtle Jowel" to "Mitch McConnell Meat Muppet". Truly, we've come leaps and bounds from the days of yore and consumption, to the tomorrow of "human centipede" model of economics and explosive diarrhea.
What time to be alive.
In terms of large, North American fast food chains, I like A&W, Carl's Jr/Hardy's, and Jack in the Box. In terms of smaller, regional chains, I think In-N-Out is leaps and bounds the best (though What-A-Burger is also really good). Outside of North America, I'm a pretty big fan of Mos Burger from Japan. JollyBee from the Philippines is also pretty great, but mostly because they serve spaghetti and I find that amusing.
I think Shake Shack is overrated but worth trying. FiveGuys is meh.
I also firmly believe that smaller burger chains like In-N-Out, Shake Shack, and What-A-Burger are probably more or less equal in terms of quality and what determines which you think is best is where you grew up.