We came for dim sum on a Saturday afternoon at 1pm, well past the early bird special time. I don't remember what we ordered in totality, but I distinctly remember that 1) the food tasted delicious and 2) the portion was big. For example, the Stir Fried Rice Noodle with Deep Fried Garlic ($7.50 on dim sum menu) was the size of a full entree. There was no "dim sum" portion going on for this order. Granted there was not much of meat in the ingredients, but the color and the taste were good. The Shao Mei ($4.80) were big, delicious and there were 4 pieces in the order. Many restaurants give you 3 pieces nowadays. One item that impressed all of us was the Pan Fried Taro Cake ($2.80). It tasted so rich of taro and the texture was so smooth.
One note is that beware of over-ordering, as the portion here is bigger than many lower priced restaurants.
For reference, I would put the dim sum at Casa Deluz on par with the traditional dim sum at Shangri-La Banquet Hall in Markham. Shangri-La features some innovative dim sum, whereas Casa Deluz offers traditional flairs.
Another thing that stood out - the tea was very good. I looked; the pot was loaded with whole Jasmine tea leaves, not chopped up tiny tea leaves bits.
The services were good during our visit. This might be because the early bird crowd was gone.
We will likely return for dim sum if we are in the neighbourhood.