In N Out all the way. And I've lived on both coasts.
In and out hands down. Double cheeseburger animal style rocks.
Make your own. In N Out came to this state two years ago and they aren't so great. Five Guys is just another corporate burger. Make your own with bacon in the meat. Serve it with a kaiser bun with cheese and jalapenos. In N Out and Five Guys don't offer beer and that is another reason to make your own burgers at home.
5 Guys for sure. They hyper here in Utah is ridiculous. It's only popular because it's from Cali...OOhhhhh ahhhhh! Phhhtt.
Have 5 guys up here and I'm not impressed. Haven't been to an In n out since I was a kid, so I don't remember those. Frankly, I think Jack in the Box has better burgers and they are far cheaper (as far as chain stores go).
I have only had either of them once...so I don't think I am really qualified to answer!! :)