Our choice is 5 Guys. Don't care for In N Out.
Applebee's has a huge burger and they are the only place you can specify Pink/Medium for the meat. About the same price as 5 Guys.
The In-n-out Burgers are good especially the animal style version but we've found the best burger in LA is in Hollywood. The Pig N Whistle on Hollywood Blvd. is by far the best burger on the west coast. Runner up would be 5 Guys and Red Robin.