That's a hard one. Five Guys has BACON! With a lot more toppings. But In-N-Out I can pig out with like 4 patties. I also prefer fries from In-N-Out. I don't like big cuts of fries in general and Five Guys tend to just overload your bag with fries.
Sorry ! Only have one In-N-Out that's far away and never heard of the other one.
Check this site for some visuals:
