Rol San was listed in many "best of" lists for Dim Sum in Toronto because of its value. Nothing on the menu is over $3.50 for a portion, and the quality is quite good at that price level. While this probably won't be the best dim sum you've ever had if you are a connoisseur, this is perfectly fine for the vast majority of eaters.
Service was quick, seating is plentiful, and there are no dim sum carts. You fill out a list, as though you were ordering sushi. Items arrive in shifts from the kitchen -- and you never know when you'll get something! Our dessert arrived in the middle of the meal, but who cares! It's fun!
Siu Mai was excellent, as was the crab and chicken soup dumpling. We did not order anything exotic, and what we saw on other tables and the smiles on other diners' faces convinced me that pretty much everything is above average here.
Not the highest food quality but still a thoroughly enjoyable experience. If you are confused by the many offerings in Chinatown, give Rol San a try -- I doubt you will be disappointed.