I stayed at a hotel nearby so I pretty much went to Yorkdale for lunch almost every single day. I felt that the food court was very spacious, clean, and designed very well but it was still quite hard to find seats sometimes.
I enjoyed the Glow Press grilled cheese eatery quite a lot, while other vendors such as Big Smoke Burger and Jimmy the Greek disappointed me. In general, I found that the prices in the food court were comparable to many of the restaurants in Toronto so I found the value to be quite low, but I guess the food court is situated in one of the most expensive malls in North America so I shouldn't complain!