I hate being the obligatory hater but....it's so overrated. The tiny hamburgers are ok at best and the fries are borderline inedible. And the..oh yeah that's all they have.
So, the burgers aren't huge, but neither is the price. You can add as many extra patties as you can handle. The quality that you get for the price at In-N-Out is great. Everything is fresh, the customer service is fantastic, the restaurants are clean. They treat their employees well, and it shows. They are happy to be there, and they treat you as such. They have never ever messed up my order. I will always be a cheerleader for In-N-Out. They are also very law enforcement friendly. It's a great company. I have never had a bad experience there. I honestly think there are people that don't want to give it a chance because it's a "California based" company. Just my $.02