In a word: small! My burger was fantastic: taste, toppings/freshness, but I wanted more. I ordered a single but felt like I needed a magnifying glass to see the beef patty. Perhaps I should have ordered a double? As far as singles go, much smaller than a single from South Street, Big Smoke, or Gangster Burger on Queen St., or the legendary Apache Burgers on Dundas St.
One other point, if I'm paying 9 bucks for a burger I'd really like a choice of buns, something other than generic plain white bread.