As a former American, I am used to PetSmart and its larger big box pet stores. When I lived in Ottawa, PetSmart was all over, but it seems to have a problem with rents in Toronto, as this is the only one in Toronto proper. So I have a choice of traveling here or to North Mississauga.
I much prefer it to PetValu, which I find small and limited. The other pet stores near my High Park address are pretty yuppy and out of my price range.
Plus, PetSmart, curiously, carries a full line of a Canadian made food which I tried by chance and really happen to like - TechniCal. Their lamb and rice dog mix has no corn (which gives my boxers and sharpei gas) and uses brown rice. It must taste good, as the dogs seem to like it more than other previous foods they were on.