I've got to say: I was underwhelmed by my last visit to Five Guys. Granted, I was there just before New Years when the whole Deerfoot Meadows area is still packed with "Boxing Week" shoppers. However, it wasn't the busyness that bothered me; it was the lack of cleanliness. I know you're busy but how hard would it be to go around wiping down the tables once in awhile? How about sweeping? Dirty restaurants like this gross me out and don't exactly invite a return visit.
That being said, the food was as good as other reviews on here rave. Tip to my fellow vegetarians: skip the veggie sandwich and opt for the grilled cheese with all the fixings. It's much more satisfying.
If I'm hungry and in the area again I would probably stop by and give the restaurant a second chance thanks to the quality of the food. I'm giving them the benefit of the doubt for now that the messiness was due to the time of year and is not standard practice. I hope I'm not wrong.