I know Toronto doesn't "do" Mexican, but if you are just looking for a decent lunch and nothing too authentic, this place is fine.
It is never very busy in La Mexicana, and usually the servers take good care of you, which is generally better than restaurants TRYING to be authentic Mexican who only manage to be authentic in terms of bad service. La Mexicana has nice competent servers.
The food is pretty good and the prices are OK - they do give you quite a lot of food.
You start off with some fresh corn chips/tortillas that are quite tasty and some salsa. Warning - the salsa in the big bowl is spicy! the salsa in the little bowl is milder.
We all had the combo platter which consists of a salad (nice dressing!), a beef burrito and a chicken enchilada, served with rice or black beans. The presentation is simple and the food tastes good. They provide some sour cream and guac and it does the job.
As I said, this is not authentic Mexican, but it's fine for a lunch with friends. It's not cheap, the lunch plates are approx $15, but they do fill you up.