Sky Dragon is probably the most reliable of the Chinatown dim sum restaurants, and is always busy - especially on weekends. The service is sporadic and the staff aren't very friendly, but it gets the job done.
I don't speak Chinese, so it's always an interesting experience when ordering from the carts that pass by. Having said that, the servers can explain each dish to you if necessary.
Nothing fancy but a decent lunch option in Chinatown that won't break the bank.