As part of my "Eating Toronto Tour", I really really wanted a burger; so went to the GBK on Church.
Place looked nice and clean and had a great selection of burgers and poutine.
I ordered both the Portabello Burger and the Lamb burger (yes, I was hungry), along with their mushroom poutine. My cousins ordered a reg burger.
My Portabello Burger: an actual grilled Portabello mushroom with brie cheese. That was really really good and juicy.
Lamb burger: lamb patty with goat cheese. That was a disappointment... the meat was super dry and lacked flavor.
The buns use for the burgers was too thick and dry.
The mushroom poutine came with 2 slices of Swiss cheese - not good! The fries were overcooked, the gravy was super salty and the cheese was like WTH?
I guess, it's a good place if you don't want fast food type of burger, but I would not go back for a "true specialty burger" place.