I don't know about that. I went to five guys once. The service was good but the hamburger just didn't cut it at all. The manager even gave me another one on the house, but no.
Are you supposed to order something in particular?
Problems with that comparison:
In n' Out is fast food, as in it almost always has a drive-thru.
5 Guys almost never has a drive-thru. It's a sit-down place. They're measured on different scales.
Now, to get down to brass tacks:
In n Out isn't worth hyping for. It's not as good as Whataburger, which is a Texas staple already. I have tried both within the same 24 hour period, with about a 5 hour window difference. (Ate In n' Out, got on a plane, got Whataburger on the way home from the airport.)
5 Guys is better than both, but it's a sit-down place, so it's on a different scale entirely.
IMHO, Whataburger is the best fast food burger. (best I've had yet, anyways) In n' Out comes in at #2. It's close, but Whataburger definitely wins.
5 Guys is the best sit-down burger chain.
Best non-chain burger, I will likely never know for certain since so many small-town diners and burger bars have so many incredibly good burgers.
Eat many burgers, my friends. Enjoy them all.