Whataburger is actually my favorite burger. Their fries and catsup is also at the top of my list. Back before I lost 100 lbs, I used to eat there regularly.
Five Guys is expensive, but look at all the toppings you get- bell peppers, jalapenos, onions, etc. In N' Out gives you a big chunk of lettice, a hunk of onion if you request it, and some Thousand Island dressing mixed with mayo and catsup. And I don't really like their fries. Good if you're hungry (we stop at the In N' Out, ironically, on the way to San Diego), but it wouldn't be my first choice.