This is one of Vancouver's best hidden gems, even though it is not so hidden anymore (they have been reviewed in the New York Times after all!)
The food is, in a word, outstanding. There is a huge variety and selection, and it is almost impossible to choose from their 7+ page, 12 point font menu in reasonable time. A word of advice: if it's your first time there and you're overwhelmed by the selection, let the server choose for you, which is what I did (it may have been the manager actually.) Every dish we received was incredible.
Also make sure to go with at least 4 people so you can all sample a reasonable number of dishes, as each are quite large and intended to be shared around.
Some nights you can experience quite a wait, and you have to be careful because the restaurant closes quite early (I think they don't let anyone in after 9pm.) In this case you either have to be patient, or make a reservation beforehand.
The layout is a bit underwhelming as it more resembles a cheap Chinese restaurant, and the menu might seem overpriced in comparison at first. But once you taste it, you will agree you're actually getting great value given the quality of the food.
I have taken many many different parties here, and everyone has always been very impressed. In case it helps, here are some of the best dishes I have tried:
-"Grandmother's recipe" garlic fried squid
-Garlic fried prawns
-Hot and sour fish soup
-Phnom Penh noodles (get dry with soup on side)
-Butter beef - like an asian style beef carpaccio, amazing