Burger: I always can get a double/double animal style. Whataburger is typically better, but several of their menu items rotate and go off schedule. Probably In N Out by a nose

Fries: Whataburger is better. And spicy ketchup is a must. Whataburger and it’s not close

Drinks: Whataburger has Dr Pepper shake.

Ambiance: In N Out kids are always nice, sometimes a wait but the drive thru line always moves. Whataburger employees are usually surly, and the wait can be long. In N Out is the clear winner

Overall: pretty even, hard to go really wrong with either one as long as you do t mind had fries (In N Out) or bad employees (Whataburger)