Depends on what you are looking for. Where are you going to be when in town? Got a car to get around? How much are you looking to spend? Want to eat at a "nicer" place or ok if it's a little run down?
We go to Fortune House Seafood Restaurant in Metrotown a lot. You order off a sheet (versus carts) so the food is usually pretty fresh. Shrimp dumplings are huge. The bill runs us around $13 to $16 per person depending if we over order or not. The lineups are nuts. Unless you make reservations or get there when it opens, you could be waiting for over 30 mins.
We go to Kirin (multiple locations) in Richmond every so often. Very good but a bit pricey at about $20 per person. 15-30 min lineups here. Order off a card. Great service and a nicer atmosphere. We ate at the Richmond location a number of times (dim sum & dinner) to scout them out for a possible wedding reception venue. (Yes, we went with them.)
Pink Pearl is not our favourite but ok and safe. We haven't been there in over a year and a half. They're one of the few places that still uses carts. The food is ok. The bills ran us around $12 to $14 and we'd rather pay a few dollars more to eat at Fortune House.
We find Sun Sui Wah over priced for dim sum for what you get. Used to run us in the high teens per person. Nice but I think they're better for dinner. Order off a card. Haven't been to the Main street one in over a year. Never been to the Richmond one.
Floata (in Richmond and Chinatown) is ok. Nothing special. Runs about low to mid teens per person. Order off a card. (Recently went to the Chinatown one for dinner in December and it didn't impress me at all though.)
The wife has eaten at Imperial Seafood a few times when she worked downtown. Nice harbour views but unsure now because of all the construction. She thought it was really good but a bit pricey (high teens). Order off a card.
A kind of a dark horse favourite is Top Gun in Crystal Mall, located near Metropolis at Metrotown. Haven't eaten there in a few months but they are kind of a trendy Hong Kong style dim sum. You won't find all the standard dim sum menu items you're used to seeing. Funky teas. Costs around high teens per person. Order off a card.
One last place I'd recommend is Fisherman's Terrace Seafood Restaurant in Aberdeen Centre in Richmond. We tried this place in December and really liked it. Very good food but kind of pricey at close to $20 per person. Order off a card.