Check out some of the all-you-can-eat Japanese/Sushi places as well. They are really competitive and much better than any of the a.y.c.e. U.S. chains.
E Bei (Granville & 41st) is highly recommended as all dishes, including all the sushi, is made to order but it is located south of downtown.
I know you asked about Chinese Dim Sum but since we were talking about Vancouver I thought I would bring up a good Japanese alternative.