I am from the home of the original Five Guys burger joint in the Washington, DC area. Now they're all over the USA and I have never been to a Five Guys anywhere that was not the same burger and fries as I had the first time I ate one when I was in Junior High. It's always consistent and I think it's the best burger you can get for under $6 anywhere.
I love In N Out. I love Five Guys just a tiny bit more.
2 different experiences (no peanuts to enjoy while you wait at In N Out and not as clean at Five Guys) and Five Guys costs more, but one order of fries and a burger might convert you if you already have a favorite burger joint.