Five Guys is one of the fastest growing new burger joints, and there's no shortage of online reviews raving about how great it is. Their claim to fame is apparently that they use peanut oil, which they like to show off with the big sacks of peanuts and cans of oil "decorating" the floor.
Even when you eat in at Five Guys, its take out. Everything is wrapped in foil and put into a lunch bag. When you order you can have them put the condiments on for you so you don't have to unwrap them; personally I like to put my own stuff on so I get the correct amount. Burgers are served on seseme seed buns and hot dogs are split and grilled. Fries are served in a paper cup. No sauerkraut for the hot dogs is a big, big minus.
The verdict: I find Five Guys to be unremarkable. There's really nothing special about it. Its certainly better than McDonalds. But I can't see myself getting all sweaty thinking about eating here. Its just pretty good.