A colleague of mine raves about Five Guys and goes there for lunch at least twice a month, despite it being well over half an hour round trip by car.
I've never been, nor to any of the other 'posh' burger places for that matter, but the one thing that surprises me about Five Guys is that they seem to be ignoring the fact that every man and his dog is vegan or vegetarian these days and the only options for vegetarians are more or less cheese and garnish in a bun.
At least all the other burger places do a couple of proper burger options.