Ding Tai Fung serves the best Xiao Long Bao (or soup dumplings) in the GTA. It is well worth the trek to Markham. The dumplings contains a savoury broth and pork. The skin is firm enugh to hold the broth yet soft (without being soggy). The dumplings are best eaten with a spoon so you don't lose the broth. The other dumplings and buns are also delectable.
The restaurant is designed for efficiency. This is not a fancy restaurant, but it is a clean restaurant. You can see the chefs preparing the dumplings and buns in the kitchen through a glass window.
Note that Ding Tai Fung is not affiliated with the Din Tai Fung in Asia (which originated in Taiwan). As an aside, Din Tai Fung in Hong Kong was awarded one Michelin Star - it is one of my favourite places to go for Xiao Long Bao in Hong Kong. It is clear that Ding Tai Fung (in Toronto) is trying to copy or at least draw inspiration from the Din Tai Fung in Asia. I would say that for the most part Ding Tai Fung has successful replicated the Din Tai Fung model.